Conductive composition and production method therefor, and water-soluble polymer and production method therefor

ABSTRACT

A conductive composition comprising a conductive polymer (A), a water-soluble polymer (B), and a solvent (C1), wherein: the water-soluble polymer (B) comprises a water-soluble polymer (B11) represented by formula (11), and an amount of a water-soluble polymer (B2) represented by formula (2) as the water-soluble polymer (B) is 0.15% by mass or less, based on a total mass of the conductive composition: 
     
       
         
         
             
             
         
       
     
     wherein R 1  denotes a linear or branched alkyl group with 6 to 20 carbon atoms, each of R 4  and R 5  independently denotes a methyl or ethyl group, R 6  denotes a hydrophilic group, R 7  denotes a hydrogen atom or a methyl group, Y 1  denotes a single bond, —S—, —S(═O)—, —C(═O)—O— or —O—, Z denotes a cyano group or a hydroxy group, each of p1 and q denotes an average number of repetitions, and is a number of from 1 to 50, and m denotes a number of from 1 to 5.

This application is a continuation application of InternationalApplication No. PCT/JP2019/002337, filed on Jan. 24, 2019, which claimspriority to Japanese Patent Application No. 2018-011446, filed Jan. 26,2018, the entire contents of which are incorporated herein by reference.

TECHNICAL FIELD

The present invention relates to a conductive composition and a methodfor producing the same, and a water-soluble polymer and a method forproducing the same.

BACKGROUND ART

Patterning techniques using charged particle beams such as electronbeams and ion beams are promising candidates of the next generationtechnology of photolithography.

For improving the productivity with the use of charged particle beams,it is important to improve the sensitivity of the resist. From thisperspective, the mainstream process uses a highly sensitive chemicallyamplified resist that is allowed to generate an acid in its area exposedto light or irradiated with the charged particle beam, which is followedby a heat treatment called “post exposure bake (PEB)” to acceleratecrosslinking reaction or decomposition reaction.

Incidentally, especially when the substrate is insulating, thepatterning method using charged particle beams has a problem that thetrajectory of the charged particle beam is bent due to an electric fieldgenerated by the charge (charge up) of the substrate, resulting indifficulty in obtaining a desired pattern.

As a means to solve this problem, there is a technique already known tobe effective, which applies a conductive composition containing aconductive polymer to a surface of a resist layer to form a coating filmso as to coat the surface of the resist layer, thereby imparting anantistatic function to the resist layer.

In general, when a conductive composition containing a conductivepolymer is applied as an antistatic agent in an electron beamlithography process for a semiconductor, there is a trade-offrelationship between the coatability of the conductive composition andthe influence thereof on a substrate or a coating layer such as a resistcoated on the substrate.

For example, the addition of an additive such as a surfactant forimproving the coatability of the conductive composition poses a problemthat the surfactant adversely affects the resist characteristics and apredetermined pattern cannot be obtained.

Addressing such a problem, Patent Document 1 proposes a conductivecomposition including a water-soluble polymer having anitrogen-containing functional group and a hydrophobic terminal group asa conductive composition that excels in coatability and the like.

DESCRIPTION OF PRIOR ART Patent Document

-   Patent Document 1: Japanese Unexamined Patent Application    Publication No. 2002-226721

DISCLOSURE OF INVENTION Problems to be Solved by the Invention

However, there is still room for improvement in the conductivity of thecoating film obtained from the conductive composition described inpatent document 1, and further improvement of the conductivity isdesired.

The purpose of the present invention is to provide a conductivecomposition which can form a coating film with excellent conductivityand has excellent coatability, and a method for producing the same.Further purpose of the present invention is to provide a water-solublepolymer contained in the conductive composition and a method forproducing the same.

Means to Solve the Problems

The embodiments of the present invention are as follows.

[1] A conductive composition including a conductive polymer (A), awater-soluble polymer (B), and a solvent (C1), wherein:

the water-soluble polymer (B) comprises a water-soluble polymer (B11)represented by formula (11), and

an amount of a water-soluble polymer (B2) represented by formula (2) asthe water-soluble polymer (B) is 0.15% by mass or less, based on a totalmass of the conductive composition:

In the formula (11), R¹ denotes a linear or branched alkyl group with 6to 20 carbon atoms, Y¹ denotes a single bond, —S—, —S(═O)—, —C(═O)—O— or—O—, p1 denotes an average number of repetitions and is a number of from1 to 50, and m denotes a number of from 1 to 5.

In the formula (2), each of R⁴ and R⁵ independently denotes a methyl orethyl group, R⁶ denotes a hydrophilic group, R⁷ denotes a hydrogen atomor a methyl group, Z denotes a cyano group or a hydroxy group, and qdenotes an average number of repetitions and is a number of from 1 to50.

[2] A conductive composition including a conductive polymer (A), awater-soluble polymer (B), a solvent (C1), and a basic compound (D),wherein:

the water-soluble polymer (B) includes a water-soluble polymer (B1)represented by formula (1), and

an amount of a water-soluble polymer (B2) represented by formula (2) asthe water-soluble polymer (B) is 0.15% by mass or less, based on a totalmass of the conductive composition:

In the formula (1), R¹ denotes a linear or branched alkyl group with 6to 20 carbon atoms, R² denotes a hydrophilic group, R³ denotes ahydrogen atom or a methyl group, Y¹ denotes a single bond, —S—, —S(═O)—,—C(═O)—O— or —O—, and p1 denotes an average number of repetitions and isa number of from 1 to 50.

In the formula (2), each of R⁴ and R⁵ independently denotes a methyl orethyl group, R⁶ denotes a hydrophilic group, R⁷ denotes a hydrogen atomor a methyl group, Z denotes a cyano group or a hydroxy group, and qdenotes an average number of repetitions and is a number of from 1 to50.

[3] The conductive composition according to [1] or [2], wherein awater/octanol partition coefficient (Log P) for polymerizationinitiator-derived components in the water-soluble polymer (B) is 8.50 ormore.[4] The conductive composition according to any one of [1] to [3],wherein the conductive polymer (A) is polyaniline sulfonic acid.[5] A water-soluble polymer represented by formula (3):

In the formula (3), R⁸ denotes a linear or branched alkyl group with 6to 20 carbon atoms, R⁹ denotes a hydrophilic group, R¹⁰ denotes ahydrogen atom or a methyl group, Y² denotes a single bond, —C(═O)—O— or—O—, and p2 denotes an average number of repetitions and is a number ofmore than 1 and not more than 50.

[6] A method for producing a water-soluble polymer (B) including awater-soluble polymer (BI) represented by formula (1), the methodincluding a polymerization step of polymerizing a water-soluble vinylmonomer in a solvent (C2) satisfying condition 1 in the presence of apolymerization initiator having a terminal hydrophobic group:

Condition 1: a chain transfer constant of methyl acrylate to the solvent(C2) at 50° C. is 0.001 or less.

In the formula (1), R¹ denotes a linear or branched alkyl group with 6to 20 carbon atoms, R² denotes a hydrophilic group, R³ denotes ahydrogen atom or a methyl group, Y¹ denotes a single bond, —S—, —S(═O)—,—C(═O)—O— or —O—, and p1 denotes an average number of repetitions and isa number of from 1 to 50.

[7] The method according to [6], wherein the polymerization step isperformed in the presence of a chain transfer agent having a terminalhydrophobic group.[8] A method for producing a conductive composition, comprising a stepof producing the water-soluble polymer (B) by the method of [6] or [7],and a step of mixing the obtained water-soluble polymer (B) with aconductive polymer (A) and a solvent (C1).

Effect of the Invention

The present invention can provide a conductive composition which canform a coating film with excellent conductivity and has excellentcoatability, and a method for producing the same. Further, the presentinvention can also provide a water-soluble polymer contained in theconductive composition and a method for producing the same.

DESCRIPTION OF THE EMBODIMENTS

Hereinbelow, the present invention will be described in detail.

In the present invention, the term “conductive” means that a volumeresistivity is 1×10¹⁰ Ω·cm or less. The volume resistivity is determinedfrom the surface resistivity determined from the potential differencebetween electrodes when a constant current is flown between theelectrodes, and the thickness of the coating film used to determine thesurface resistivity.

In the present invention, the term “water/octanol partition coefficient(Log P) for polymerization initiator-derived components in thewater-soluble polymer (B)” refers to a concentration ratio of thepolymerization initiator-derived components in water and octanol whenthe water-soluble polymer (B) is dissolved in a mixture of water andoctanol (mixing ratio is arbitrary). In the present invention, the term“Log P” refers to a value calculated with CambridgeSoft's ChemDraw Pro12.0.

Further, in the context of the present specification, the term“solubility” means that 0.1 g or more of a substance dissolves uniformlyin 10 g (liquid temperature 25° C.) of simple water, water containing atleast one of a base and a basic salt, water containing an acid, or amixture of water and a water-soluble organic solvent. Furthermore, theterm “water-soluble” means the solubility in water in relation to theaforementioned solubility.

In the context of the present specification, the “terminal” of the“terminal hydrophobic group” means a molecular terminal or a site otherthan repeating units constituting a polymer.

Further, in the context of the present specification, the term “weightaverage molecular weight” refers to a weight average molecular weight(in terms of sodium polystyrene sulfonate or polyethylene glycol) asmeasured by gel permeation chromatography (GPC).

Conductive Composition First Embodiment

The conductive composition of the first embodiment of the presentinvention includes a conductive polymer (A), a water-soluble polymer(B), and a solvent (C1), which are described below. The conductivecomposition may, if necessary, further include a basic compound (D), apolymeric compound (B), and optional components, which are describedbelow.

<Conductive Polymer (A)>

Examples of the conductive polymer (A) include polypyrrole,polythiophene, polythiophene vinylene, polytellurophene, polyphenylene,polyphenylene vinylene, polyaniline, polyacene, polyacetylene and thelike.

Among these, polypyrrole, polythiophene and polyaniline are preferablefrom the viewpoint of excellent conductivity.

Specific examples of monomers (raw material monomers) constitutingpolypyrrole include pyrrole, N-methylpyrrole, 3-methylpyrrole,3-ethylpyrrole, 3-n-propylpyrrole, 3-butylpyrrole, 3-octylpyrrole,3-decylpyrrole, 3-dodecylpyrrole, 3,4-dimethylpyrrole,3,4-dibutylpyrrole, 3-carboxypyrrole, 3-methyl-4-carboxypyrrole,3-methyl-4-carboxyethylpyrrole, 3-methyl-4-carboxybutylpyrrole,3-hydroxypyrrole, 3-methoxypyrrole, 3-ethoxypyrrole, 3-butoxypyrrole,3-hexyloxypyrrole, 3-methyl-4-hexyloxypyrrole and the like.

Specific examples of monomers (raw material monomers) constitutingpolythiophene include thiophene, 3-methylthiophene, 3-ethylthiophene,3-propylthiophene, 3-butylthiophene, 3-hexylthiophene,3-heptylthiophene, 3-octylthiophene, 3-decylthiophene,3-dodecylthiophene, 3-octadecylthiophene, 3-bromothiophene,3-chlorothiophene, 3-iodothiophene, 3-cyanothiophene, 3-phenylthiophene,3,4-dimethylthiophene, 3,4-dibutylthiophene, 3-hydroxythiophene,3-methoxythiophene, 3-ethoxythiophene, 3-butoxythiophene,3-hexyloxythiophene, 3-heptyloxythiophene, 3-octyloxythiophene,3-decyloxythiophene, 3-dodecyloxythiophene, 3-octadecyloxythiophene,3,4-dihydroxythiophene, 3,4-dimethoxythiophene, 3,4-diethoxythiophene,3,4-dipropoxythiophene, 3,4-dibutoxythiophene, 3,4-dihexyloxythiophene,3,4-diheptyloxythiophene, 3,4-dioctyloxythiophene,3,4-didecyloxythiophene, 3,4-didodecyloxythiophene,3,4-ethylenedioxythiophene, 3,4-propylenedioxythiophene,3,4-butenedioxythiophene, 3-methyl-4-methoxythiophene,3-methyl-4-ethoxythiophene, 3-carboxythiophene,3-methyl-4-carboxythiophene, 3-methyl-4-carboxyethylthiophene,3-methyl-4-carboxybutylthiophene,6-(2,3-dihydro-thieno[3,4-b][1,4]dioxin-2-yl)hexane-1-sulfonic acid,6-(2,3-dihydro-thieno[3,4-b][1,4]dioxin-2-yl)hexane-1-sulfonic acidsodium salt,6-(2,3-dihydro-thieno[3,4-b][1,4]dioxin-2-yl)hexane-1-sulfonic acidlithium salt,6-(2,3-dihydro-thieno[3,4-b][1,4]dioxin-2-yl)hexane-1-sulfonic acidpotassium salt,8-(2,3-dihydro-thieno[3,4-b][1,4]dioxin-2-yl)octane-1-sulfonic acid,8-(2,3-dihydro-thieno[3,4-b][1,4]dioxin-2-yl)octane-1-sulfonic acidsodium salt, 8-(2,3-dihydro-thieno [3,4-b] [1,4]dioxin-2-yl)octane-1-sulfonic acid potassium salt,3-[(2,3-dihydrothieno[3,4-b]-[1,4]dioxin-2-yl)methoxy]-1-propanesulfonicacid sodium salt,3-[(2,3-dihydrothieno[3,4-b]-[1,4]dioxin-2-yl)methoxy]-1-propanesulfonicacid potassium salt,3-[(2,3-dihydrothieno[3,4-b]-[1,4]dioxin-2-yl)methoxy]-1-methyl-1-propanesulfonicacid sodium salt,3-[(2,3-dihydrothieno[3,4-b]-[1,4]dioxin-2-yl)methoxy]-1-ethyl-1-propanesulfonicacid sodium salt,3-[(2,3-dihydrothieno[3,4-b]-[1,4]dioxin-2-yl)methoxy]-1-propyl-1-propanesulfonicacid sodium salt,3-[(2,3-dihydrothieno[3,4-b]-[1,4]dioxin-2-yl)methoxy]-1-butyl-1-propanesulfonicacid sodium salt,3-[(2,3-dihydrothieno[3,4-b]-[1,4]dioxin-2-yl)methoxy]-1-pentyl-1-propanesulfonicacid sodium salt,3-[(2,3-dihydrothieno[3,4-b]-[1,4]dioxin-2-yl)methoxy]-1-hexyl-1-propanesulfonicacid sodium salt,3-[(2,3-dihydrothieno[3,4-b]-[1,4]dioxin-2-yl)methoxy]-1-isopropyl-1-propanesulfonicacid sodium salt,3-[(2,3-dihydrothieno[3,4-b]-[1,4]dioxin-2-yl)methoxy]-1-isobutyl-1-propanesulfonicacid sodium salt,3-[(2,3-dihydrothieno[3,4-b]-[1,4]dioxin-2-yl)methoxy]-1-isopentyl-1-propanesulfonicacid sodium salt, 3-[(2,3-dihydrothieno[3,4-b]-[1,4]dioxin-2-yl)methoxy]-1-fluoro-1-propanesulfonic acid sodiumsalt, 3-[(2,3-dihydrothieno [3,4-b]-[1,4]dioxin-2-yl)methoxy]-1-methyl-1-propane sulfonate potassium salt.3-[(2,3-dihydrothieno[3,4-b]-[1,4]dioxy-2-yl)methoxy]-1-methyl-1-propanesulfonicacid salt, 3-[(2,3-dihydrothieno[3,4-b]-[1,4] dioxin-2-yl)methoxy]-1-methyl-1-propanesulfonic acid ammonium salt,3-[(2,3-dihydrothieno[3,4-b]-[1,4]dioxin-2-yl)methoxy]-2-methyl-1-propanesulfonicacid sodium salt,3-[(2,3-dihydrothieno[3,4-b]-[1,4]dioxin-2-yl)methoxy]-1-methyl-1-propanesulfonicacid triethylammonium salt,4-[(2,3-dihydrothieno[3,4-b]-[1,4]dioxin-2-yl)methoxy]-1-butanesulfonicacid sodium salt,4-[(2,3-dihydrothieno[3,4-b]-[1,4]dioxin-2-yl)methoxy]-1-butanesulfonicacid potassium salt,4-[(2,3-dihydrothieno[3,4-b]-[1,4]dioxin-2-yl)methoxy]-1-methyl-1-butanesulfonicacid sodium salt,4-[(2,3-dihydrothieno[3,4-b]-[1,4]dioxin-2-yl)methoxy]-1-methyl-1-butanesulfonicacid potassium salt,4-[(2,3-dihydrothieno[3,4-b]-[1,4]dioxin-2-yl)methoxy]-1-fluoro-1-butanesulfonicacid sodium salt, and4-[(2,3-dihydrothieno[3,4-b]-[1,4]dioxin-2-yl)methoxy]-1-fluoro-1-butanesulfonicacid potassium salt, and the like.

Specific examples of monomers (raw material monomers) constitutingpolyaniline include aniline, 2-methylaniline, 3-isobutylaniline,2-methoxyaniline, 2-ethoxyaniline, 2-anilinesulfonic acid,3-anilinesulfonic acid and the like.

The conductive polymer (A) preferably has water solubility or waterdispersibility. When the conductive polymer (A) has water solubility orwater dispersibility, the coatability of the conductive composition isenhanced, and a coating film having a uniform thickness can be easilyobtained.

The conductive polymer (A) preferably has an acidic group. When theconductive polymer (A) has an acidic group, the water solubility can beenhanced.

The conductive polymer having an acidic group is not particularlylimited as long as the polymer has at least one group selected from thegroup consisting of a sulfonic acid group and a carboxy group in itsmolecule and the effects of the present invention can be obtained, andthe examples thereof preferable from the viewpoint of solubility includeconductive polymers described in Japanese Patent Unexamined PublicationNos. Sho 61-197633, Sho 63-39916, Hei 1-301714, Hei 5-504153, Hei5-503953, Hei 4-32848, Hei 4-328181, Hei 6-145386, Hei 6-56987, Hei5-226238, Hei 5-178989, Hei 6-293828, Hei 7-118524, Hei 6-32845, Hei6-87949, Hei 6-256516, Hei 7-41756, Hei 7-48436, Hei 4-268331, and2014-65898.

Specific examples of the conductive polymer having an acidic groupinclude n-conjugated conductive polymers containing, as repeating units,at least one type of monomers selected from the group consisting ofphenylene vinylene, vinylene, thienylene, pyrrolylene, phenylene,iminophenylene, isothianaphthene, furylene, and carbazolylene, eachhaving its α position or β position substituted with at least one groupselected from the group consisting of a sulfonic acid group and acarboxy group.

When the n-conjugated conductive polymer contains at least one repeatingunit selected from the group consisting of iminophenylene andcarbazolylene, examples thereof include a conductive polymer having atleast one group selected from the group consisting of a sulfonic acidgroup and a carboxy group on the nitrogen atoms of the repeating units,and a conductive polymer having an alkyl group (or an etherbond-containing alkyl group) substituted with at least one groupselected from the group consisting of a sulfonic acid group and acarboxy group on the nitrogen atoms of the repeating units.

Among these, from the perspective of conductivity and solubility, it ispreferable to use conductive polymers having at least one type ofmonomer unit selected from the group consisting of thienylene,pyrrolylene, iminophenylene, phenylenevinylene, carbazolylene, andisothianaphthene, each having its β position substituted with at leastone group selected from the group consisting of a sulfonic acid groupand a carboxy group.

The conductive polymer (A) preferably has at least one type of monomerunit selected from the group consisting of monomer units represented bythe following formulae (4) to (7) from the perspective of conductivityand solubility.

In the formulae (4) to (7), X represents a sulfur atom or a nitrogenatom, and each of R¹¹ to R² independently represents a hydrogen atom, alinear or branched alkyl group having 1 to 24 carbon atoms, a linear orbranched alkoxy group having 1 to 24 carbon atoms, an acidic group, ahydroxy group, a nitro group, a halogen atom (—F, —Cl —Br or —I),—N(R²⁶)₂, —NHCOR²⁶, —SR²⁶, —OCOR²⁶, —COOR²⁶, —COR²⁶, —CHO or —CN. R²⁶ ispreferably an alkyl group having 1 to 24 carbon atoms, an aryl grouphaving 6 to 24 carbon atoms, or an aralkyl group having 7 to 24 carbonatoms.

However, at least one of R¹¹ and R¹² in the formula (4), at least one ofR¹ to R¹⁶ in the formula (5), at least one of R¹⁷ to R²⁰ in the formula(6), and at least one of R²¹ to R²⁵ in the formula (7) are each anacidic group or a salt thereof.

The “acidic group” means a sulfonic acid group (sulfo group) or acarboxylic acid group (carboxy group).

The sulfonic acid group may be present in an acid form (—SO₃H) or anionic form (—SO₃ ⁻). Further, the sulfonic acid group also encompasses asubstituent having a sulfonic acid group (—R²⁷SO₃H).

On the other hand, the carboxylic acid group may be present in an acidform (—COOH) or an ionic form (—COO⁻). Further, the carboxylic acidgroup also encompasses a substituent having a carboxylic acid group(—R²⁷COOH).

R²⁷ represents a linear or branched alkylene group having 1 to 24 carbonatoms, a linear or branched arylene group having 6 to 24 carbon atoms,or a linear or branched aralkylene group having 7 to 24 carbon atoms.

Examples of the salt of acidic group include alkali metal salts,alkaline earth metal salts, ammonium salts, and substituted ammoniumsalts of a sulfonic acid group or a carboxylic acid group.

Examples of the alkali metal salt include lithium sulfate, lithiumcarbonate, lithium hydroxide, sodium sulfate, sodium carbonate, sodiumhydroxide, potassium sulfate, potassium carbonate, potassium hydroxideand derivatives having skeletons thereof.

Examples of the alkaline earth metal salt include magnesium salts,calcium salts and the like.

Examples of the substituted ammonium salt include aliphatic ammoniumsalts, saturated alicyclic ammonium salts, unsaturated alicyclicammonium salts and the like.

Examples of the aliphatic ammonium salts include methyl ammonium,dimethyl ammonium, trimethyl ammonium, ethyl ammonium, diethyl ammonium,triethyl ammonium, methyl ethyl ammonium, diethyl methyl ammonium,dimethyl ethyl ammonium, propyl ammonium, dipropyl ammonium, isopropylammonium, diisopropyl ammonium, butyl ammonium, dibutyl ammonium, methylpropyl ammonium, ethyl propyl ammonium, methyl isopropyl ammonium, ethylisopropyl ammonium, methyl butyl ammonium, ethyl butyl ammonium,tetramethyl ammonium, tetramethylol ammonium, tetra ethyl ammonium,tetra n-butyl ammonium, tetra sec-butyl ammonium, tetra t-butylammonium, and the like.

Examples of the saturated alicyclic ammonium salts include piperidinium,pyrrolidinium, morpholinium, piperazinium, and derivatives havingskeletons thereof.

Examples of the unsaturated alicyclic ammonium salts include pyridinium,α-picolinium, β-picolinium, γ-picolinium, quinolinium, isoquinolinium,pyrrolinium, and derivatives having skeletons thereof.

The conductive polymer (A) preferably has a monomer unit represented bythe above formula (7) since high conductivity can be achieved. Among themonomer units represented by the above formula (7), from the perspectiveof excellent solubility, especially preferred is a monomer unitrepresented by the following formula (8).

In the formula (8), each of R²⁸ to R³¹ independently represents ahydrogen atom, a linear or branched alkyl group having 1 to 24 carbonatoms, a linear or branched alkoxy group having 1 to 24 carbon atoms, anacidic group, a hydroxy group, a nitro group or a halogen atom (—F, —Cl—Br or —I). At least one of R²⁸ to R³¹ is an acidic group or a saltthereof.

As for the monomer unit represented by the above formula (8), it ispreferable in terms of easy production that any one of R²⁸ to R³¹ is alinear or branched alkoxy group having 1 to 4 carbon atoms, whileanother one of R²⁸ to R³¹ is a sulfonic acid group, and the remainder ishydrogen.

In the conductive polymer (A), for achieving very good solubility, thenumber of acid group-bonded aromatic rings is preferably 50% or more,more preferably 70% or more, still more preferably 90% or more, and mostpreferably 100%, relative to the total number of aromatic rings presentin the polymer.

The number of acid group-bonded aromatic rings relative to the totalnumber of aromatic rings present in the polymer refers to a valuecalculated from the compounding ratio of monomers at the production ofthe conductive polymer (A).

Further, with respect to substituents on the aromatic rings of themonomer units in the conductive polymer (A), the substituents other thanthe acidic group are preferably electron donating groups for impartingreactivity to the monomers. Specifically, the substituents arepreferably alkyl groups having 1 to 24 carbon atoms, alkoxy groupshaving 1 to 24 carbon atoms, halogen groups (—F, —Cl, —Br or —I) and thelike, and alkoxy groups having 1 to 24 carbon atoms are most preferablefrom the perspective of electron donation.

The conductive polymer (A) is preferably a compound having a structurerepresented by the following formula (9) since high conductivity andsolubility can be achieved. Further preferable among the compoundshaving a structure represented by the formula (9) is a polyanilinehaving a sulfonic acid group, that is, polyaniline sulfonic acid, andpoly(2-sulfo-5-methoxy-1,4-iminophenylene) is particularly preferable.

In the formula (9), each of R³² to R⁴⁷ independently represents ahydrogen atom, a linear or branched alkyl group having 1 to 4 carbonatoms, a linear or branched alkoxy group having 1 to 4 carbon atoms, anacidic group, a hydroxy group, a nitro group or a halogen atom (—F, —Cl—Br or —I). At least one of R³² to R⁴⁷ is an acidic group or a saltthereof. Further, n represents a polymerization degree. In the presentinvention, n is preferably an integer of 5 to 2500.

It is desirable that at least a part of the acidic groups contained inthe conductive polymer (A) is in a free acid form from the perspectiveof conductivity improvement.

From the perspective of conductivity, solubility and film formability,the weight average molecular weight of the conductive polymer (A) ispreferably 1,000 to 1,000,000, more preferably 1,500 to 800,000, stillmore preferably 2,000 to 500,000, and particularly preferably 2,000 to100,000, in terms of sodium polystyrene sulfonate as determined by GPC.When the weight average molecular weight of the conductive polymer (A)is less than 1000, good solubility may be achieved, but the conductivityand the film formability may be insufficient. On the other hand, whenthe weight average molecular weight exceeds 1,000,000, good conductivitymay be achieved, but the solubility may be insufficient.

The term “film formability” refers to an ability to form a uniform filmwithout cissing etc., which can be evaluated by a method such as spincoating on glass.

As for the method for producing the conductive polymer (A), there is noparticular limitation and any known method can be employed as long asthe desired effects of the present invention are available.

Specific examples of the method include a method of polymerizingpolymerizable monomers (raw material monomers) capable of forming any ofthe above monomer units by various synthesis methods such as a chemicaloxidation method, an electrolytic oxidation method and the like. As suchmethod, for example, the synthesis methods described in JapaneseUnexamined Patent Application Publication Nos. Hei 7-196791 and Hei7-324132 can be adopted.

An example of method for producing the conductive polymer (A) will bedescribed below.

For example, the conductive polymer (A) can be obtained by polymerizingraw material monomers using an oxidizing agent in the presence of abasic reaction auxiliary.

Examples of the basic reaction auxiliary include inorganic bases (e.g.,sodium hydroxide, potassium hydroxide, lithium hydroxide, etc.),ammonia, aliphatic amines, cyclic saturated amines, and cyclicunsaturated amines.

Examples of the oxidant include peroxodisulfuric acids (e.g.,peroxodisulfuric acid, ammonium peroxodisulfate, sodium peroxodisulfate,potassium peroxodisulfate, etc.), hydrogen peroxide, etc.

Examples of the polymerization method includes a method of dropping amixture of raw material monomers and a basic reaction auxiliary into anoxidant solution, a method of dropping an oxidant solution into amixture of raw material monomers and a basic reaction auxiliary, and amethod of dropping a mixture of raw material monomers and a basicreaction auxiliary as well as an oxidant solution into a reaction vesselsimultaneously.

After the polymerization, the solvent is usually separated by aseparation device such as a centrifugal separator. The conductivepolymer (A) is obtained by drying the filtered material after washing itwith a washing solution if necessary.

The conductive polymer (A) obtained in this manner may contain lowmolecular weight materials such as raw material monomers (unreactedmonomers), oligomers formed by side reactions, the oxidant, and thebasic reaction auxiliary. These low molecular weight materials inhibitthe conductivity.

Therefore, it is preferable to purify the conductive polymer (A) toremove the low molecular weight materials.

The method for purifying the conductive polymer (A) is not particularlylimited, any purification methods can be employed, such as ion exchangemethod, acid cleaning in a protonic acid solution, removal by heattreatment, and neutralization and precipitation; however, the ionexchange method is particularly effective because a highly-purifiedconductive polymer (A) can obtained with ease.

Examples of the ion exchange method include column or batch treatmentsusing ion exchange resins such as cation exchange resins and anionexchange resins; electrodialysis methods, etc.

When the conductive polymer (A) is purified by the ion exchange method,it is preferable to dissolve a reaction mixture obtained by thepolymerization in an aqueous medium to a desired solids concentration,and then allow the resulting polymer solution to contact an ion exchangeresin.

The aqueous media may be water, an organic solvent, or a solvent mixtureof water and an organic solvent. The organic solvent may be the same asthe solvent (C1) described below.

The concentration of the conductive polymer (A) in the polymer solutionis preferably 0.1 to 20% by mass, and more preferably 0.1 to 10% by massfrom the viewpoint of industrial efficiency and purification efficiency.

The amount of the conductive polymer (A), based on a total mass of theconductive composition, is preferably 0.1 to 5% by mass, more preferably0.2 to 3% by mass, and even more preferably 0.5 to 2% by mass.

The amount of the conductive polymer (A), based on a total mass of solidcomponents of the conductive composition, is preferably 50 to 99.9% bymass, more preferably 80 to 99.9% by mass, and even more preferably 95to 99.9% by mass. The solid components of the conductive composition area residue obtained by removing the solvent (C1) from the conductivecomposition.

When the amount of the conductive polymer (A) is within the rangedescribed above, an excellent balance is achieved between thecoatability of the conductive composition and the conductivity of acoating film formed from the conductive composition.

<Water-Soluble Polymer (B)>

The water-soluble polymer (B) includes a water-soluble polymer (B11)shown below and, optionally, a water-soluble polymer (B2) shown below.

In this context, the term “optionally” means that the water-solublepolymer (B) may or may not contain the water-soluble polymer (B2). Inother words, the water-soluble polymer (B) may contain the water-solublepolymer (B11) while being substantially free of the water-solublepolymer (B2), or may be a mixture of the water-soluble polymer (B11) andthe water-soluble polymer (B2).

As described later in detail, the water-soluble polymer (B) is obtainedby polymerizing the water-soluble vinyl monomers in a specific solventin the presence of a polymerization initiator having a terminalhydrophobic group.

The water/octanol partition coefficient (Log P) for polymerizationinitiator-derived components in the water-soluble polymer (B) ispreferably 8.50 or more, and more preferably 9.0 to 20.0. When thewater/octanol partition coefficient for polymerization initiator-derivedcomponents is not less than the lower limit value described above, thesurface activity is more likely to be exhibited.

(Water-soluble polymer (B11)) The water-soluble polymer (B11) is acompound represented by the following formula (11).

In the formula (11), R¹ denotes a linear or branched alkyl group with 6to 20 carbon atoms, Y¹ denotes a single bond, —S—, —S(═O)—, —C(═O)—O— or—O—, p1 denotes an average number of repetitions and is a number of from1 to 50, and m denotes a number of from 1 to 5.

R¹ is a hydrophobic substituent. In other words, the water-solublepolymer (B11) is a compound having a terminal hydrophobic group and ahydrophilic groups within its molecule, and is likely to exhibit surfaceactivity. Therefore, the presence of the water-soluble polymer (B11) inthe conductive composition improve the coatability the coatingcomposition on a substrate and the like. Moreover, while conventionalsurfactants (e.g., dodecylbenzene sulfonic acid) may have an adverseeffect on the resist characteristics, such an adverse effect on theresist characteristics can be easily suppressed by the use of thewater-soluble polymer (B11).

Examples of the alkyl group as R¹ include a hexyl group, a cyclohexylgroup, a 2-ethylhexyl group, a n-octyl group, a lauryl group, a dodecylgroup, a tridecyl group, a stearyl group, an isobornyl group, and thelike.

In the formula (11), p1 is a number of from 1 to 50, preferably 2 ormore, and more preferably 4 or more. Further, p1 is preferably 30 orless, and more preferably 20 or less. Particularly when p1 is greaterthan or equal to 2, the surface activity is further improved.

The value of p1 can be controlled by adjusting the ratio (molar ratio)of the polymerization initiator used for the polymerization of thewater-soluble polymer (B) to the water-soluble vinyl monomer.

The weight average molecular weight of the water-soluble polymer (B11)is preferably 100 to 1,000,000, more preferably 100 to 100,000, evenmore preferably 600 or more and less than 20,000, and particularlypreferably 600 or more and less than 10,000, in terms of polyethyleneglycol in GPC. When the weight average molecular weight of thewater-soluble polymer (B11) is not less than the lower limit valuedescribed above, the effect of improving the coatability of theconductive composition can be more easily achieved. On the other hand,when the weight average molecular weight of the water-soluble polymer(B11) is not more than the upper limit value described above, the watersolubility of the conductive composition is enhanced. In particular,when the weight average molecular weight of the water-soluble polymer(B11) is 600 or more and less than 10000, an excellent balance isachieved between the practical solubility thereof in water and thecoatability of the conductive composition.

The amount of the water-soluble polymer (B11), based on a total mass ofthe conductive composition, is preferably 0.001 to 2% by mass, morepreferably 0.001 to 0.5% by mass, and even more preferably 0.001 to 0.3%by mass.

Further, the amount of the water-soluble polymer (B11), based on a totalmass of solid components of the conductive composition, is preferably0.1 to 60% by mass, more preferably 0.1 to 50% by mass, and even morepreferably 0.1 to 40% by mass.

When the amount of the water-soluble polymer (B11) is within the rangedescribed above, an excellent balance is achieved between thecoatability of the conductive composition and the conductivity of acoating film formed from the conductive composition.

(Water-Soluble Polymer (B2))

The water-soluble polymer (B2) is a compound represented by thefollowing formula (2).

In the formula (2), each of R⁴ and R⁵ independently denotes a methyl orethyl group, R⁶ denotes a hydrophilic group, R⁷ denotes a hydrogen atomor a methyl group, Z denotes a cyano group or a hydroxy group, and qdenotes an average number of repetitions and is a number of from 1 to50.

R⁶ is a hydrophilic group. The hydrophilic group is derived from thewater-soluble vinyl monomer, which is the raw material monomer of thewater-soluble polymer (B11).

In this context, the “water-soluble vinyl monomer” refers to a vinylmonomer that can be mixed with water at a certain ratio. Examples of thewater-soluble vinyl monomer that is the raw material monomer of thewater-soluble polymer (B11) include N-vinyl pyrrolidone, N-vinylpiperidinone, N-vinyl caprolactam, N-vinyl-2-azacyclooctanone,N-vinyl-2-azacycuronanone, and the like.

The amount of the water-soluble polymer (B2) in the water-solublepolymer (B), based on a total mass of the conductive composition, is0.15% by mass or less, i.e., 0 to 0.15% by mass, preferably 0 to 0.1% bymass, more preferably 0 to 0.05% by mass, and it is even more preferablethat the water-soluble polymer (B) is substantially free of thewater-soluble polymer (B2). In this context, the term “substantiallyfree” means that the amount of the water-soluble polymer (B2), based onthe total mass of the conductive composition, is less than 0.005% bymass. In other words, the amount of the water-soluble polymer (B2) inthe water-soluble polymer (B) is preferably 0% by mass or more and lessthan 0.005% by mass, based on the total mass of the conductivecomposition.

When the amount of the water-soluble polymer (B2) is within the rangedescribed above, an excellent balance is achieved between thecoatability of the conductive composition and the conductivity of thecoating film.

The amount of the water-soluble polymer (B2) in the water-solublepolymer (B), based on a total mass of solid components of the conductivecomposition, is preferably 7% by mass or less, i.e., 0 to 7% by mass,more preferably 0 to 1% by mass, and it is even more preferable that thewater-soluble polymer (B) is substantially free of the water-solublepolymer (B2). In this context, the term “substantially free” means thatthe amount of the water-soluble polymer (B2), based on the total mass ofsolid components of the conductive composition, is less than 0.1% bymass. In other words, the amount of the water-soluble polymer (B2) inthe water-soluble polymer (B) is preferably 0% by mass or more and lessthan 0.1% by mass, based on the total mass of solid components of theconductive composition.

When the amount of the water-soluble polymer (B2) is within the rangedescribed above, an excellent balance is achieved between thecoatability of the conductive composition and the conductivity of thecoating film.

<Solvent (C1)>

The solvent (C1) is not particularly limited as long as it can dissolvethe conductive polymer (A) and the water-soluble polymer (B) and theeffects of the present invention can be obtained, and examples thereofinclude water and a mixed solvent of water and an organic solvent.

Examples of the organic solvent include alcohols such as methanol,ethanol, isopropyl alcohol, propyl alcohol and butanol; ketones such asacetone and ethyl isobutyl ketone; ethylene glycols such as ethyleneglycol and ethylene glycol methyl ether; propylene glycols such aspropylene glycol, propylene glycol methyl ether, propylene glycol ethylether, propylene glycol butyl ether and propylene glycol propyl ether;amides such as dimethylformamide and dimethylacetamide; and pyrrolidonessuch as N-methylpyrrolidone and N-ethylpyrrolidone.

When a mixed solvent of water and an organic solvent is used as thesolvent (C1), the mass ratio of water to an organic solvent(water/organic solvent) is preferably 1/100 to 100/1, and morepreferably 2/100 to 100/2.

The amount of the solvent (C1) is preferably 1 to 99% by mass, morepreferably 10 to 98% by mass, and even more preferably 50 to 98% bymass, based on a total mass of the conductive composition.

When the amount of the solvent (C1) is within the range described above,the coatability further improves.

<Basic Compound (D)>

If necessary, a basic compound (D) may be added to the conductivecomposition. When the conductive polymer (A) has an acidic group, thebasic compound (D) serves to generate a salt with the acidic group toneutralize the acidic group. By neutralization, the influence on theresist can be suppressed.

The basic compound (D) is not particularly limited, but when theconductive polymer (A) has an acidic group, the basic compound (D)preferably includes at least one selected from the group consisting of aquaternary ammonium salt (d-1), a basic compound (d-2), and a basiccompound (d-3), which are described below, because the formation of asalt with the acidic group is facilitated, thereby stabilizing theacidic group to achieve excellent effect of preventing acidic substancesderived from the film from affecting the resist pattern.

Quaternary ammonium salt (d-1): a quaternary ammonium compound in whichat least one of the four substituents bonded to the nitrogen atom is ahydrocarbon group having 1 or more carbon atoms.

Basic compound (d-2): a basic compound having one or more nitrogen atoms(exclusive of the quaternary ammonium salt (d-1) and the basic compound(d-3)).

Basic compound (d-3): a basic compound having a basic group and two ormore hydroxy groups in the same molecule and a melting point of 30° C.or higher.

In the quaternary ammonium compound (d-1), the nitrogen atom to whichthe four substituents are bonded is a nitrogen atom of the quaternaryammonium ion.

Examples of the hydrocarbon group bonded to the nitrogen atom of thequaternary ammonium ion in the compound (d-1) include an alkyl group, anaralkyl group and an aryl group.

Examples of the quaternary ammonium compound (d-1) includetetrapropylammoniumhydroxide, tetrabutylammoniumhydroxide,tetrapentylammonium hydroxide, tetrahexylammonium hydroxide,benzyltrimethylammonium hydroxide and the like.

Examples of the basic compound (d-2) includes ammonia, pyridine,triethylamine, 4-dimethylaminopyridine, 4-dimethylaminomethylpyridine,3,4-bis(dimethylamino)pyridine, 4-hydroxypyridine, 4-methylpyridine,1,5-diazabicyclo[4.3.0]-5-nonene (DBN),1,8-diazabicyclo[5.4.0]-7-undecene (DBU), and derivatives thereof.

In the basic compound (d-3), the basic group may be, for example, abasic group defined as an Arrhenius base, a Brønsted base, a Lewis base,etc. Specific examples include ammonia, etc. The hydroxy group may be inthe state of —OH or may be protected by a protective group. Examples ofthe protective groups include an acetyl group; a silyl group such as atrimethyl silyl group, a tert-butyl dimethyl silyl group, etc.; anacetal-type protective group such as a methoxymethyl group, anethoxymethyl group, a methoxyethoxymethyl group, etc.; a benzoyl group;an alkoxide group, etc.

Examples of the basic compound (d-3) includes 2-amino-1,3-propanediol,tris(hydroxymethyl)aminomethane, 2-amino-2-methyl-1,3-propanediol,2-amino-2-ethyl-1,3-propanediol,3-[N-tris(hydroxymethyl)methylamino]-2-hydroxypropanesulfonic acid, andN-tris(hydroxymethyl)methyl-2-aminoethanesulfonic acid.

One of these basic compounds may be used alone, or two or more of themmay be used in the form of a mixture thereof with an appropriateblending ratio.

In particular, since it is easier to form a salt with the acidic groupof the conductive polymer (A), it is preferable that the basic compound(D) includes at least one species selected from the group consisting ofthe quaternary ammonium salt (d-1) and the basic compound (d-2).

As the basic compound (D), basic compounds other than the quaternaryammonium compound (d-1), the basic compound (d-2) and the basic compound(d-3) may also be mixed.

The amount of the basic compound (D) is preferably 0.1 to 70% by mass,and more preferably 0.1 to 50% by mass, based on a total mass of solidcomponents of the conductive composition.

When the amount of the basic compound (D) is within the range describedabove, an excellent balance is achieved between the coatability of theconductive composition and the conductivity of a coating film formedfrom the conductive composition. In particular, when the amount of thebasic compound (D) is not less than the lower limit value describedabove, a coating film with less influence on the resist pattern can beformed.

<Polymeric Compound (E)>

The conductive composition may include a polymer compound (E), ifnecessary, for the purpose of further improving the strength and surfacesmoothness of the coating film.

Specific examples of the polymer compound (E) include polyvinyl alcoholderivatives such as polyvinyl formal and polyvinyl butyral,polyacrylamides such as polyacrylamide, poly(N-t-butyl acrylamide) andpolyacrylamide methyl propane sulfonate, polyvinyl pyrrolidones,polyacrylic acids, water-soluble alkyd resins, water-soluble melamineresins, water-soluble urea resins, water-soluble phenol resins,water-soluble epoxy resins, water-soluble polybutadiene resins,water-soluble acrylic resins, water-soluble urethane resins,water-soluble acrylic styrene copolymer resins, water-soluble vinylacetate acrylic copolymer resins, and water-soluble polyester resins,water-soluble styrene maleic acid copolymer resins, water-soluble fluororesins, and copolymers thereof.

<Optional Component>

Further, the conductive composition may optionally contain any ofvarious additives, such as a pigment, an antifoaming agent, anultraviolet light absorber, an antioxidant, a heat resistance improver,a leveling agent, an antidripping agent, a matting agent, and apreservative.

In the present invention, the sum of amounts of the conductive polymer(A), the water-soluble polymer (B), and the solvent (C1) in theconductive composition of the first embodiment of the invention does notexceed 100% by mass of the total mass of the conductive composition.When the conductive composition contains at least one of the basiccompound (D), the polymeric compound (E), and the optional component,the sum of the amounts of the conductive polymer (A), the water-solublepolymer (B), the solvent (C1), the basic compound (D), the polymericcompound (E), and the optional component in the conductive compositiondoes not exceed 100% by mass of the total mass of the conductivecomposition.

Further, the amounts of all components of the conductive composition addup to 100% by mass.

<Effects>

As described later in detail, the water-soluble polymer (B) can beobtained by polymerizing the water-soluble vinyl monomers. As a resultof intensive studies, the present inventors have found out that thewater-soluble polymer (B2) may be generated during the production of thewater-soluble polymer (B) in addition to the water-soluble polymer (B11)which is the target product, and the water-soluble polymer (B) isobtained in the form of a mixture of the water-soluble polymer (B11) andthe water-soluble polymer (B2). Therefore, when the water-solublepolymer (B) is used for production of a conductive composition, thewater-soluble polymer (B2) is also unintentionally allowed to be mixedin the conductive composition. The present inventors made a study on thewater-soluble polymer (B2) and found that the water-soluble polymer (B2)has a low surface activity. Therefore, when the produced water-solublepolymer (B) is used in a conductive composition without removing thewater-soluble polymer (B2), a large amount of the water-soluble polymer(B) must be blended in order to achieve sufficient surface activity. Ifthe water-soluble polymer (B2) is removed from the water-soluble polymer(B), even a small amount of the water-soluble polymer (B) enables asufficient surface activity. However, for example, the purification bythe reprecipitation method cannot easily separate the water-solublepolymer (B11) from the water-soluble polymer (B2), and requirescumbersome operation to remove the water-soluble polymer (B2).

The conductive composition of the first embodiment of the inventioncontains the conductive polymer (A), the water-soluble polymer (B11),and the solvent (C1), which are described above, and the amount of thewater-soluble polymer (B2) is specified as 0.15% by mass or less, basedon the total mass of the conductive composition. This means that, evenwhen the water-soluble polymer (B) obtained by polymerizing thewater-soluble vinyl monomers is used as it is in a conductivecomposition without purification treatment to intentionally remove thewater-soluble polymer (B2), the amount of the water-soluble polymer (B2)is sufficiently reduced. In other words, it means that the generation ofthe water-soluble polymer (B2) is suppressed during the production ofthe water-soluble polymer (B). Therefore, even if the water-solublepolymer (B) is used without purification treatment to intentionallyremove the water-soluble polymer (B2), a sufficient surface activity canbe achieved with only a small amount of the water-soluble polymer (B).Further, since the amount of the water-soluble polymer (B) can bereduced, the proportion of the conductive polymer (A) to the total massof solid components of the conductive composition increases relativelyand the conductivity of the coating film improves.

Second Embodiment

The conductive composition of the second embodiment of the presentinvention includes a conductive polymer (A), a water-soluble polymer(B), a solvent (C1), and a basic compound (D) which are described below.The conductive composition may, if necessary, further include apolymeric compound (E), and optional components, which are describedbelow.

The explanations on the conductive polymer (A), the solvent (C1) and thebasic compound (D) in the conductive composition of the secondembodiment of the present invention are omitted, because these are thesame as the conductive polymer (A), the solvent (C1) and the basiccompound (D) described above in the explanations on the conductivecomposition of the first embodiment of the present invention.

Likewise, the explanations on the polymeric compound (E) and theoptional components that may, if necessary, be contained in theconductive composition of the second embodiment of the present inventionare omitted, because these are the same as the polymeric compound (E)and the optional components described above in the explanations on theconductive composition of the first embodiment of the present invention.

<Water-Soluble Polymer (B)>

The water-soluble polymer (B) includes a water-soluble polymer (B1)shown below and, optionally, a water-soluble polymer (B2) shown below.

In this context, the term “optionally” means that the water-solublepolymer (B) may or may not contain the water-soluble polymer (B2). Inother words, the water-soluble polymer (B) may contain the water-solublepolymer (B1) while being substantially free of the water-soluble polymer(B2), or may be a mixture of the water-soluble polymer (B1) and thewater-soluble polymer (B2).

As described later in detail, the water-soluble polymer (B) is obtainedby polymerizing the water-soluble vinyl monomers in a specific solventin the presence of a polymerization initiator having a terminalhydrophobic group.

The water/octanol partition coefficient (Log P) for polymerizationinitiator-derived components in the water-soluble polymer (B) ispreferably 8.50 or more, and more preferably 9.0 to 20.0. When thewater/octanol partition coefficient for polymerization initiator-derivedcomponents is not less than the lower limit value described above, thesurface activity is more likely to be exhibited.

(Water-Soluble Polymer (B1))

The water-soluble polymer (B1) is a compound represented by thefollowing formula (1).

In the formula (1), R¹ denotes a linear or branched alkyl group with 6to 20 carbon atoms, R² denotes a hydrophilic group, R³ denotes ahydrogen atom or a methyl group, Y¹ denotes a single bond, —S—, —S(═O)—,—C(═O)—O— or —O—, and p1 denotes an average number of repetitions and isa number of from 1 to 50.

R¹ is a hydrophobic substituent. In other words, the water-solublepolymer (B1) is a compound having a terminal hydrophobic group and ahydrophilic groups within its molecule, and is likely to exhibit surfaceactivity. Therefore, the presence of the water-soluble polymer (B1) inthe conductive composition improves the coatability of the coatingcomposition on a substrate and the like. Moreover, while conventionalsurfactants (e.g., dodecylbenzene sulfonic acid) may have an adverseeffect on the resist characteristics, such an adverse effect on theresist characteristics can be easily suppressed by the use of thewater-soluble polymers (B1).

Examples of the alkyl group as R¹ include a hexyl group, a cyclohexylgroup, a 2-ethylhexyl group, a n-octyl group, a lauryl group, a dodecylgroup, a tridecyl group, a stearyl group, an isobornyl group, and thelike.

R² is a hydrophilic group. The hydrophilic group is derived from thewater-soluble vinyl monomer, which is the raw material monomer of thewater-soluble polymer (B1).

In this context, the “water-soluble vinyl monomer” refers to a vinylmonomer that can be mixed with water at a certain ratio. Examples of thewater-soluble vinyl monomer that is the raw material monomer of thewater-soluble polymer (B1) include N-vinylpyrrolidone, 2-hydroxyethyl(meth)acrylate, (meth)acrylamide, N,N-dimethylacrylamide, acryloylmorpholine, and N-vinylformamide.

In the formula (11), p1 is a number of from 1 to 50, preferably 2 ormore, and more preferably 4 or more. Further, p1 is preferably 30 orless, and more preferably 20 or less. Particularly when p1 is greaterthan or equal to 2, the surface activity is further improved.

The value of p1 can be controlled by adjusting the ratio (molar ratio)of the polymerization initiator used for the polymerization of thewater-soluble polymer (B) to the water-soluble vinyl monomer.

The weight average molecular weight of the water-soluble polymer (B1) ispreferably 100 to 1,000,000, more preferably 100 to 100,000, andparticularly preferably 600 or more and less than 10,000, in terms ofpolyethylene glycol in GPC. When the weight average molecular weight ofthe water-soluble polymer (B1) is not less than the lower limit valuedescribed above, the effect of improving the coatability of theconductive composition can be more easily achieved. On the other hand,when the weight average molecular weight of the water-soluble polymer(B1) is not more than the upper limit value described above, the watersolubility of the conductive composition is enhanced. In particular,when the weight average molecular weight of the water-soluble polymer(BI) is 600 or more and less than 2000, an excellent balance is achievedbetween the practical solubility thereof in water and the coatability ofthe conductive composition.

The water-soluble polymer (B1) is preferably the water-soluble polymer(B11) represented by the formula (11) described above in theexplanations on the conductive composition of the first embodiment ofthe present invention from the perspective of solubility and the like.

The amount of the water-soluble polymer (B1), based on a total mass ofthe conductive composition, is preferably 0.001 to 1% by mass, morepreferably 0.001 to 0.3% by mass, and even more preferably 0.01 to 0.1%by mass.

Further, the amount of the water-soluble polymer (B1), based on a totalmass of solid components of the conductive composition, is preferably0.1 to 20% by mass, more preferably 0.1 to 5% by mass, and even morepreferably 0.1 to 2% by mass.

When the amount of the water-soluble polymer (B1) is within the rangedescribed above, an excellent balance is achieved between thecoatability of the conductive composition and the conductivity of acoating film formed from the conductive composition.

(Water-Soluble Polymer (B2))

The water-soluble polymer (B2) is a compound represented by thefollowing formula (2).

In the formula (2), each of R⁴ and R⁵ independently denotes a methyl orethyl group, R⁶ denotes a hydrophilic group, R⁷ denotes a hydrogen atomor a methyl group, Z denotes a cyano group or a hydroxy group, and qdenotes an average number of repetitions and is a number of from 1 to50.

R⁶ is a hydrophilic group. The hydrophilic group is derived from thewater-soluble vinyl monomer, which is the raw material monomer of thewater-soluble polymer (B1). As examples of the water-soluble vinylmonomer, those mentioned above in the explanation on the water-solublepolymer (B1) can be listed.

The amount of the water-soluble polymer (B2) in the water-solublepolymer (B), based on a total mass of the conductive composition, is0.15% by mass or less, i.e., 0 to 0.15% by mass, preferably 0 to 0.1% bymass, more preferably 0 to 0.05% by mass, and it is even more preferablethat the water-soluble polymer (B) is substantially free of thewater-soluble polymer (B2). In this context, the term “substantiallyfree” means that the amount of the water-soluble polymer (B2), based onthe total mass of the conductive composition, is less than 0.005% bymass. In other words, the amount of the water-soluble polymer (B2) inthe water-soluble polymer (B) is preferably 0% by mass or more and lessthan 0.005% by mass, based on the total mass of the conductivecomposition.

When the amount of the water-soluble polymer (B2) is within the rangedescribed above, an excellent balance is achieved between thecoatability of the conductive composition and the conductivity of thecoating film.

The amount of the water-soluble polymer (B2) in the water-solublepolymer (B), based on a total mass of solid components of the conductivecomposition, is preferably 7% by mass or less, i.e., 0 to 7% by mass,more preferably 0 to 1% by mass, and it is even more preferable that thewater-soluble polymer (B) is substantially free of the water-solublepolymer (B2). In this context, the term “substantially free” means thatthe amount of the water-soluble polymer (B2), based on the total mass ofsolid components of the conductive composition, is less than 0.1% bymass. In other words, the amount of the water-soluble polymer (B2) inthe water-soluble polymer (B) is preferably 0% by mass or more and lessthan 0.1% by mass, based on the total mass of solid components of theconductive composition.

When the amount of the water-soluble polymer (B2) is within the rangedescribed above, an excellent balance is achieved between thecoatability of the conductive composition and the conductivity of thecoating film.

In the present invention, the sum of amounts of the conductive polymer(A), the water-soluble polymer (B), the solvent (C1) and the basiccompound (D) in the conductive composition of the second embodiment ofthe invention does not exceed 100% by mass of the total mass of theconductive composition. When the conductive composition contains atleast one of the polymeric compound (E), and the optional component, thesum of the amounts of the conductive polymer (A), the water-solublepolymer (B), the solvent (C1), the basic compound (D), the polymericcompound (E), and the optional component in the conductive compositiondoes not exceed 100% by mass of the total mass of the conductivecomposition.

Further, the amounts of all components of the conductive composition addup to 100% by mass.

<Effects>

As described later in detail, the water-soluble polymer (B) can beobtained by polymerizing the water-soluble vinyl monomers. As a resultof intensive studies, the present inventors have found out that thewater-soluble polymer (B2) may be generated during the production of thewater-soluble polymer (B) in addition to the water-soluble polymer (B1)which is the target product, and the water-soluble polymer (B) isobtained in the form of a mixture of the water-soluble polymer (B1) andthe water-soluble polymer (B2). Therefore, when the water-solublepolymer (B) is used for production of a conductive composition, thewater-soluble polymer (B2) is also unintentionally allowed to be mixedin the conductive composition. The present inventors made a study on thewater-soluble polymer (B2) and found that the water-soluble polymer (B2)has a low surface activity. Therefore, when the produced water-solublepolymer (B) is used in a conductive composition without removing thewater-soluble polymer (B2), a large amount of the water-soluble polymer(B) must be blended in order to achieve sufficient surface activity. Ifthe water-soluble polymer (B2) is removed from the water-soluble polymer(B), even a small amount of the water-soluble polymer (B) enables asufficient surface activity. However, for example, the purification bythe reprecipitation method cannot easily separate the water-solublepolymer (B1) from the water-soluble polymer (B2), and requirescumbersome operation to remove the water-soluble polymer (B2).

The conductive composition of the second embodiment of the inventioncontains the conductive polymer (A), the water-soluble polymer (B1), thesolvent (C1), and the basic compound (D), which are described above, andthe amount of the water-soluble polymer (B2) is specified as 0.15% bymass or less, based on the total mass of the conductive composition.This means that, even when the water-soluble polymer (B) obtained bypolymerizing the water-soluble vinyl monomers is used as it is in aconductive composition without purification treatment to intentionallyremove the water-soluble polymer (B2), the amount of the water-solublepolymer (B2) is sufficiently reduced. In other words, it means that thegeneration of the water-soluble polymer (B2) is suppressed during theproduction of the water-soluble polymer (B). Therefore, even if thewater-soluble polymer (B) is used without purification treatment tointentionally remove the water-soluble polymer (B2), a sufficientsurface activity can be achieved with only a small amount of thewater-soluble polymer (B). Further, since the amount of thewater-soluble polymer (B) can be reduced, the proportion of theconductive polymer (A) to the total mass of solid components of theconductive composition increases relatively and the conductivity of thecoating film improves.

[Method for Producing Water-Soluble Polymer]

The third embodiment of the present invention relates to a method forproducing a water-soluble polymer, i.e., a method for producing theaforementioned water-soluble polymer (B) including the water-solublepolymer (B1), which includes a polymerization step of polymerizing awater-soluble vinyl monomer in a solvent (C2) in the presence of apolymerization initiator having a terminal hydrophobic group.

The polymerization step may be performed in the presence of a chaintransfer agent having a terminal hydrophobic group.

As examples of the water-soluble vinyl monomer used in thepolymerization step, those mentioned above in the explanations on thewater-soluble polymer (B1) can be listed. For example, when N-vinylpyrrolidone is used as the water-soluble vinyl monomer, a water-solublepolymer (B) including the aforementioned water-soluble polymer (B11)(wherein min the formula (11) is 1) as the water-soluble polymer (B1)can be obtained.

<Solvent (C2)>

The solvent (C2) used in the polymerization step is a solvent thatsatisfies the condition 1 below.

Condition 1: a chain transfer constant of methyl acrylate to the solvent(C2) at 50° C. is 0.001 or less.

Examples of the solvent (C2) include ethyl acetate, methyl isobutylketone, acetone, methanol, ethanol, butanol, toluene, butyl acetate, andmethyl ethyl ketone.

One of these may be used alone, or two or more of these may be used incombination.

In the present invention, a solvent (C3) that does not meet thecondition 1 may be used together with the solvent (C2) in thepolymerization step as long as the effect of the invention is notimpaired.

The solvent (C3) is a solvent with a chain transfer constant of methylacrylate thereto at 50° C. exceeding 0.001. Examples of such a solvent(C3) include isopropyl alcohol, diphenylamine, N,N-dimethylaniline,triethylamine, tributylphosphine, nitrotoluene, nitroaniline,nitrobenzene, nitrophenol, and the like.

When the solvent (C2) and the solvent (C3) are used together, the volumeratio of the solvent (C2) to the solvent (C3), i.e., solvent(C2):solvent (C3), is preferably 1:0.01 to 1:1, more preferably 1:0.05to 1:0.8, and more preferably 1:0.1 to 1:0.5.

<Polymerization Initiator>

The polymerization initiator used in the polymerization step has aterminal hydrophobic group. Examples of the polymerization initiatorinclude those having a linear or branched chain alkyl group having 6 to20 carbon atoms and not having a cyano group or a hydroxy group, andmore specific examples include dilauroyl peroxide,1,1,3,3-tetramethylbutyl hydroperoxide, di-tert-hexyl peroxide,di-(2-ethylhexyl)peroxydicarbonate, 1,1,3,3-tetramethylbutylperoxyneodecanoate, di(3,5,5-trimethylhexanoyl) peroxide, and the like.

One of these may be used alone, or two or more of these may be used incombination.

As mentioned above, the value of p1 in the formula (1) described aboveand the formula (11) described above can be controlled by adjusting theratio (molar ratio) of the polymerization initiator and thewater-soluble vinyl monomer. The ratio of the polymerization initiatorto the water-soluble vinyl monomer is not particularly limited as longas the value of p1 is in the range of 1 to 50. For example, the molarratio, polymerization initiator:water-soluble vinyl monomer, ispreferably 0.001:1 to 0.5:1, and more preferably 0.01:1 to 0.1:1.

<Chain Transfer Agent>

The chain transfer agent used in the polymerization step has a terminalhydrophobic group. Examples of such a chain transfer agent include thosehaving a linear or branched chain alkyl group having 6 to 20 carbonatoms and not having a cyano group or a hydroxy group, and more specificexamples include n-dodecyl mercaptan, tert-dodecyl mercaptan, n-octylmercaptan, 2-ethylhexyl mercaptan, n-octadecyl mercaptan, etc.

One of these may be used alone, or two or more of these may be used incombination.

The ratio of the chain transfer agent to the water-soluble vinyl monomeris not particularly limited. For example, the molar ratio, chaintransfer agent:water-soluble vinyl monomer, is preferably 0.001:1 to0.1:1, and more preferably 0.01:1 to 0.05:1.

<Polymerization Conditions>

The polymerization temperature in the polymerization step is preferably50 to 200° C., and more preferably 60 to 150° C. The polymerization timeis preferably 1 to 10 hours, and more preferably 3 to 8 hours.

After the polymerization reaction, the polymer (B) is obtained byremoving the solvent (C2). The obtained polymer (B) may be subjected toa treatment in which the polymer (B) is dissolved in a good solvent tomake a water-soluble polymer solution, and the water-soluble polymersolution is added to a poor solvent to produce a precipitate, which isthen filtered, washed and dried. Such a treatment yields thewater-soluble polymer (B) in solid form.

<Effects>

As mentioned above, the water-soluble polymer (B2) may be formed duringthe production of the water-soluble polymer (B). As a result of furtherintensive studies, the present inventors have found out that R¹ and Y¹in the formula (1) and the formula (11) as well as R⁴, R⁵ and Z in theformula (2) are derived from the polymerization initiator and the chaintransfer agent used in the production of the water-soluble polymer.

The present inventors have also found out that some types of solventsused during the polymerization can also act as a chain transfer agentand can be the sources of R, Y¹, R⁴, R⁵ and Z.

According to the water-soluble polymer production method of the thirdembodiment of the present invention, the water-soluble vinyl monomersare polymerized using the specific solvent (C2) and the specificpolymerization initiator, thereby allowing the water-soluble polymer(B1) to be preferentially produced while suppressing the formation ofthe water-soluble polymer (B2).

For example, azo-based polymerization initiators, such asazobisisobutyronitrile and azobismethylbutyronitrile, generally used aspolymerization initiators are polymerization initiators having ahydrophilic group such as a cyano group. Therefore, for example, whenazobisisomethylbutyronitrile is used as the polymerization initiator,the resulting water-soluble polymer (B2) has an ethyl group as R⁴ in theformula (2), a methyl group as R⁵, and a cyano group as Z.

When the water-soluble vinyl monomers are polymerized in the presence ofa chain transfer agent having a terminal hydrophobic group andazobisisobutyronitrile, the water-soluble polymer (B) is obtained in theform of a mixture of the water-soluble polymer (B1) and thewater-soluble polymer (B2).

As for a solvent, the solvent (C3), which does not satisfy the condition1 above, tends to show its function as a chain transfer agent.Therefore, for example, when isopropyl alcohol, which is generally usedin the polymerization reaction, is used as the solvent (C3), a chaintransfer reaction occurs to produce a water-soluble polymer (B2) inwhich R⁴ and R⁵ in the formula (2) are methyl groups and Z is a hydroxygroup.

When the water-soluble vinyl monomers are polymerized in isopropylalcohol in the presence of a polymerization initiator having a terminalhydrophobic group, the water-soluble polymer (B) is obtained in the formof a mixture of the water-soluble polymer (B1) and the water-solublepolymer (B2).

Therefore, although the solvent (C2) and solvent (C3) may be usedtogether in the polymerization step, it is preferable to use only thesolvent (C2).

[Method for Producing Conductive Composition]

The fourth embodiment of the present invention relates to a method forproducing a conductive composition, which includes a step of producing awater-soluble polymer (B) by the method of the third embodiment of theinvention described above, and a step of mixing the obtainedwater-soluble polymer (B) with the conductive polymer (A) and thesolvent (C1) (mixing step).

In the mixing step, it is preferable that the conductive polymer (A),the water-soluble polymer (B) and the solvent (C1) are mixed such thatthe respective amounts thereof fall within the ranges described in theexplanations on the conductive compositions of the first embodiment ofthe present invention or the conductive composition of the secondembodiment of the present invention. Further, if necessary, at least oneof the basic compound (D), the polymeric compound (E) and the optionalcomponents may also be mixed.

<Effects>

The conductive composition production method of the fourth embodiment ofthe present invention uses the water-soluble polymer (B) produced by theaforementioned water-soluble polymer production method of the thirdembodiment of the present invention, which prevents the water-solublepolymer (B2) from being mixed in.

Therefore, a conductive composition with the amount of the water-solublepolymer (B2) being suppressed to 0.15% by mass or less can be producedwith high productively.

[Water-Soluble Polymer]

The fifth embodiment of the present invention relates to a water-solublepolymer which is a compound represented by the following formula (3).

In the formula (3), R⁸ denotes a linear or branched alkyl group with 6to 20 carbon atoms, R⁹ denotes a hydrophilic group, R¹⁰ denotes ahydrogen atom or a methyl group, Y² denotes a single bond, —C(═O)—O— or—O—, and p2 denotes an average number of repetitions and is a number ofmore than 1 and not more than 50.

As examples of the alkyl group R⁸, those mentioned above in theexplanations on the water-soluble polymer (B1) can be listed.

R⁹ is a hydrophilic group. The hydrophilic group is derived from thewater-soluble vinyl monomer, which is the raw material monomer of thewater-soluble polymer (B1). As examples of the water-soluble vinylmonomer, those mentioned above in the explanation on the water-solublepolymer (B1) can be listed.

In the formula (3), p2 is a number of more than 1 and 50 or less,preferably 2 or more, and more preferably 4 or more. Further, p2 ispreferably 30 or less, and more preferably 20 or less. In particular,when p2 is 2 or more, the surface activity further improves.

The weight average molecular weight of the water-soluble polymer of thefifth embodiment of the invention is preferably 100 and 1,000,000, morepreferably 100 to 100,000, and particularly preferably 600 and 10,000.When the weight average molecular weight of the water-soluble polymer isnot less than the lower limit value described above, the conductivecomposition using the water-soluble polymer is more likely to show theeffect of improving coatability. On the other hand, when the weightaverage molecular weight of the water-soluble polymer is not more thanthe upper limit value described above, the water solubility of theconductive composition is enhanced.

In particular, when the weight average molecular weight of thewater-soluble polymer is 600 or more and less than 2000, an excellentbalance is achieved between the practical solubility thereof in waterand the coatability of the conductive composition.

From the viewpoint of solubility etc., the water-soluble polymer of thefifth embodiment of the present invention is preferably thewater-soluble polymer (B11), of which a compound of the formula (11)wherein R¹ is a linear or branched alkyl group having 6 to 20 carbonatoms, Y¹ is a single bond, —C(═O)—O— or —O—, and p1 is a number or morethan 1 and 50 or less is particularly preferable.

The water-soluble polymer of the fifth embodiment of the presentinvention can be produced by the same method as the water solublepolymer production method of the third embodiment of the presentinvention. In the production, the p2 value is controlled by adjustingthe ratio (molar ratio) of the polymerization initiator to thewater-soluble vinyl monomer.

[Coating Film and Conductor]

The coating film (conductive coating film) obtained according to thepresent invention is formed from the conductive composition of the firstor the second embodiment of the present invention.

The conductor obtained according to the present invention is obtained bycoating or impregnating at least a part of a substrate with theconductive composition of the first or second embodiment of the presentinvention to form a coating film (conductive coating film) on thesubstrate. The conductor may have a resist layer formed on the coatingfilm.

The substrate is not particularly limited as long as the effects of thepresent invention are obtained. Examples of the substrate include moldedarticles and films of various polymers such as polyester resins (e.g.,PET and PBT), polyolefin resins represented by polyethylene andpolypropylene, vinyl chloride, nylon, polystyrene, polycarbonate, epoxyresins, fluoro resins, polysulfone, polyimide, polyurethane, phenolresins, silicon resins, and synthetic papers; and papers, iron, glass,quartz glass, various wafers, aluminum, copper, zinc, nickel, stainlesssteel and the like; and products obtainable by coating surfaces of thesesubstrates with various coating materials, photosensitive resins,resists and the like.

The shape of the substrate is not particularly limited and may be aplate or any other shape.

When the substrate is a plate, the coating film may be formed over theentire surface of one side of the substrate, or formed on a part of oneside of the substrate. The coating film may also be formed on at least apart of the other side of the substrate. Further, the coating film maybe formed on at least a part of the sides of the substrate.

When the substrate has a shape other than a plate, the coating film maybe formed over the entire surface of the substrate or on a part of thesurface of the substrate.

The method of applying the conductive composition to the substrate orimpregnating the substrate with the conductive composition is notparticularly limited as long as the effects of the present invention areobtained. Examples of the method include spin coating, spray coating,dip coating, roll coating, gravure coating, reverse coating, roll brushmethod, air knife coating and curtain coating.

The application of the conductive composition to the substrate or theimpregnation of the substrate with the conductive composition may beperformed before or during the process of producing the substrate, suchas uniaxial stretching, biaxial stretching, molding, or embossing, ormay be performed on the produced substrate after the aforementionedprocess.

Further, the conductive composition can be used to form a coating filmby overcoating the substrate which has already been coated with variouscoating materials or photosensitive materials.

As for the method for producing the conductor, the conductor can beproduced by a method in which the conductive composition is applied toor impregnated into at least a part of the substrate and dried to form acoating film, and allowed to stand for 1 minute to 60 minutes at normaltemperature (25° C.) or subjected to heat treatment.

The heating temperature for the heat treatment is preferably in therange of 40° C. to 250° C., and more preferably in the range of 60° C.to 200° C., from the perspective of conductivity. Further, the time forheat treatment is preferably within 1 hour, and more preferably within30 minutes, from the perspective of stability.

Other embodiments of the present invention are as enumerated below.

<1> A conductive composition including a conductive polymer (A), awater-soluble polymer (B), and a solvent (C1), wherein:

the water-soluble polymer (B) includes a water-soluble polymer (B11)represented by the formula (11) described above, and

an amount of a water-soluble polymer (B2) represented by the formula (2)described above as the water-soluble polymer (B) is 0.15% by mass orless, based on a total mass of the conductive composition.

<2> The conductive composition of <1> above, wherein the amount of thewater-soluble polymer (B11) is 0.001 to 2% by mass, based on a totalmass of the conductive composition.<3> The conductive composition of <1> or <2> above, wherein the amountof the water-soluble polymer (B11) is 0.1 to 60% by mass, based on atotal mass of solid components of the conductive composition.<4> A conductive composition including a conductive polymer (A), awater-soluble polymer (B), a solvent (C1), and a basic compound (D),wherein:

the water-soluble polymer (B) includes a water-soluble polymer (B1)represented by the formula (1) described above, and

an amount of a water-soluble polymer (B2) represented by the formula (2)described above as the water-soluble polymer (B) is 0.15% by mass orless, based on a total mass of the conductive composition.

<5> The conductive composition of <4> above, wherein the amount of thewater-soluble polymer (B1) is 0.001 to 1% by mass, based on a total massof the conductive composition.<6> The conductive composition of <4> or <5> above, wherein the amountof the water-soluble polymer (B1) is 0.1 to 20% by mass, based on atotal mass of solid components of the conductive composition.<7> The conductive composition of any one of <4> to <6> above, whereinthe amount of the basic compound (D) is 0.1 to 70% by mass or less,based on a total mass of solid components of the conductive composition.<8> The conductive composition according to any one of <4> to <7>,wherein the water-soluble polymer (B1) is a water-soluble polymer (B11)represented by formula (11).<9> The conductive composition according to any one of <1> to <8> above,wherein the amount of the conductive polymer (A) is 0.1 to 5% by mass orless, based on a total mass of the conductive composition.<10> The conductive composition according to any one of <1> to <9>above, wherein the amount of the conductive polymer (A) is 50 to 99.9%by mass or less, based on a total mass of solid components of theconductive composition.<11> The conductive composition according to any one of <1> to <10>above, wherein the amount of the water-soluble polymer (B2) is less than0.005% by mass, based on a total mass of the conductive composition.<12> The conductive composition of any one of <1> to <11> above, whereinthe amount of the water-soluble polymer (B2) is 7% by mass or less,based on a total mass of solid components of the conductive composition.<13> The conductive composition according to any one of <1> to <12>above, wherein the amount of the solvent (C1) is 1 to 99% by mass, basedon a total mass of the conductive composition.<14> The conductive composition according to any one of <1> to <13>above, wherein a water/octanol partition coefficient (Log P) forpolymerization initiator-derived components in the water-soluble polymer(B) is 8.50 or more.<15> The conductive composition according to any one of <1> to <14>,wherein the conductive polymer (A) is polyaniline sulfonic acid.<16> The conductive composition according to any one of <1> to <15>,wherein the conductive polymer (A) has a unit represented by the formula(7).<17> A method for producing a water-soluble polymer (B) comprising awater-soluble polymer (B1) represented by the formula (1), the methodincluding a polymerization step of polymerizing a water-soluble vinylmonomer in a solvent (C2) satisfying condition 1 in the presence of apolymerization initiator having a terminal hydrophobic group:

Condition 1: a chain transfer constant of methyl acrylate to the solvent(C2) at 50° C. is 0.001 or less.

<18> The method of <17> above, wherein the molar ratio of thepolymerization initiator to the water-soluble vinyl monomer(polymerization initiator:water-soluble vinyl monomer) is 0.001:1 to0.5:1.<19> The method according to <17> or <18>, wherein the polymerizationstep is performed in the presence of a chain transfer agent having aterminal hydrophobic group.<20> The method of <19> above, wherein the molar ratio of the chaintransfer agent to the water-soluble vinyl monomer (chain transferagent:water-soluble vinyl monomer) is 0.001:1 to 0.1:1.<21> The method of any one of <17> to <20> above, wherein a solvent (C3)not satisfying the condition 1 is used in combination with the solvent(C2) in the polymerization step.<22> The method of <21> above, wherein the volume ratio of the solvent(C2) to the solvent (C3) (solvent (C2):solvent (C3)) is 1:0.01 to 1:1.<23> A method for producing a conductive composition, including a stepof producing the water-soluble polymer (B) by the method of any one of<17> to <22>, and a step of mixing the obtained water-soluble polymer(B) with a conductive polymer (A) and a solvent (C1).<24> The method of <23> above, which further includes mixing with abasic compound (D).<25> A water-soluble polymer represented by the formula (3).<26> The water-soluble polymer of <25> above, which is a water-solublepolymer (B11) represented by the formula (11).<27> A coating film formed of the conductive composition of any one of<1> to <16> above.<28> A conductor including a substrate and a coating film of <27> aboveformed on the substrate.<29> The conductor of <28> above, which further includes a resist layerformed on the coating film.<30> A method for producing a conductor, which includes coating orimpregnating at least a part of a substrate with the conductivecomposition of any one of <1> to <16> above, followed by drying to forma coating film.<31> The method of <30> above, which further includes forming a resistlayer on the coating film.

EXAMPLES

Hereinbelow, the present invention will be specifically described inmore detail by way of Examples which should not be construed as limitingthe present invention.

The various measurements and evaluations were performed in the Examplesand Comparative Examples by respective methods as described below.

[Measurement and Evaluation Methods] <Evaluation of Coatability>

10 mL of a measurement sample was poured into a 30 mL petri dish.

The surface tension was measured by the plate method (Wilhelmy method)using a surface tension meter while keeping the temperature of themeasurement sample at 25° C.

<Evaluation of Conductivity>

1.3 mL of the conductive polymer solution or the conductive compositionwas dropped onto a 4-inch silicon wafer as a substrate, and spin-coatedon the substrate so as to cover the entire surface of the substrateusing a spin coater under the condition of 2000 rpm for 60 seconds. Theresulting was heat-treated on a hot plate at 80° C. for 2 minutes toform a coating film with a thickness of about 20 nm on the substrate.

The surface resistivity [Ω/□] of the coating film was measured by the2-terminal method (distance between the electrodes=20 mm) using HirestaX-MCP-HT800 (manufactured by Mitsubishi Chemical Analytech Co., Ltd.).

<Evaluation of Influence on Resist Layer: Visual Evaluation> (VisualEvaluation Method)

Using a chemically amplified electron beam resist (hereinafter simplyreferred to as “resist”), the influence of the conductive film on aresist layer was visually evaluated following the steps (1A) to (4A)described below.

(1A) Formation of resist layer: a resist was spin-coated onto a 4-inchsilicon wafer so as to give a resist thickness of 0.2 μm using a spincoater at 2000 rpm for 60 seconds, followed by pre-baking at 130° C. for90 seconds on a hot plate to remove the solvent and form a resist layeron the substrate.(2A) Formation of conductive film: 2 μL of a conductive composition wasdropped onto the resist layer, and spin-coated on the resist layer so asto cover a part of the entire surface of the resist layer using a spincoater under the condition of 2000 rpm for 60 seconds. The resulting washeat-treated on a hot plate at 80° C. for 3 minutes to form a conductivefilm with a thickness of about 30 nm on the resist layer.(3A) Washing with water: The conductive film was washed by running 20 mLof water, and spun at 2,000 rpm for 60 seconds using a spin coater toremove water from the surface of the resist layer.(4A) Evaluation of resist layer after removal of conductive film: Theresist layer was visually observed with respect to its portion fromwhich the coated conductive film had been removed as well as its portionwhich had not been coated with the conductive film. The results wereevaluated as (A) indicating no influence when no film color changeoccurred or (B) indicating the presence of influence when film colorchange occurred.

<Analysis of Water-Soluble Polymer (B)> (Measurement of Mass Ratio ofWater-Soluble Polymer (B1) and Water-Soluble Polymer (B2))

The water-soluble polymer (B) was analyzed by high performance liquidchromatography under the following conditions. The structures of thepeaks were determined by a mass spectrometer, and the mass ratio of thewater-soluble polymer (B1) and the water-soluble polymer (B2) wasdetermined by a charged particle detector.

<<Analysis Conditions>>

-   -   Column: C18 reversed-phase column (ODS)    -   Mobile phase: A=water, B=acetonitrile/isopropyl alcohol=50/50        (vol %), gradient analysis from A (98% by mass)+B (2% by mass)        to B (100% by mass)    -   Detectors: Mass spectrometer (TOF-MS) and charged particle        Detector (CAD)

(Measurement of Molecular Weight of Water-Soluble Polymer (B))

A 0.1% by mass aqueous solution of the water-soluble polymer (B) wasfiltered through a 0.45 μm membrane filter to prepare a sample. The GPCanalysis of the sample was performed under the conditions describedbelow to measure the weight average molecular weight of thewater-soluble polymer (B).

<<GPC Measurement Conditions>>

-   -   Measuring apparatus: TOSOH GPC-8020 (manufactured by Tosoh        Corporation)    -   Eluent: 0.2 M-NaNO₃-DIW/acetonitrile=80/20 (v/v)    -   Column temperature: 30° C.    -   Calibration curve: prepared using EasiVial™ polyethylene        glycol/oxide (manufactured by PolymerLab)

Production of Conductive Polymer (A) Production Example 1: Production ofConductive Polymer (a-1)

100 nmol of 2-aminoanisole-4-sulfonic acid was dissolved in 4 mol/L ofan aqueous ammonia solution at 25° C. to obtain a monomer solution, 100mmol of an aqueous solution of ammonium peroxodisulfate was dropped intothe obtained monomer solution. After completion of the dropwiseaddition, the resulting mixture was further stirred at 25° C. for 12hours to obtain a reaction mixture containing a conductive polymer.Thereafter, the conductive polymer was separated from the reactionmixture by a centrifugal filter. The obtained conductive polymer waswashed with methanol and then dried to obtain 15 g of a powderyconductive polymer (a-1).

The conductive polymer (a-1) was dissolved in 0.2 mol/L of aqueousammonia to thereby prepare a conductive polymer solution. The obtainedconductive polymer solution was used to form a coating film, and thesurface resistivity thereof was measured.

The volume resistivity was found to be 9.0 Ω-cm, which was obtained bymultiplying the surface resistivity by the film thickness.

Production of Water-Soluble Polymer (B) Production Example 2: Productionof Water-Soluble Polymer (b-1)

55 g (0.49 mol) of N-vinyl pyrrolidone as a water-soluble vinyl monomer,3 g (7.53 mmol) of dilauroyl peroxide as a polymerization initiator, and1 g (4.94 mmol) of n-dodecyl mercaptan as a chain transfer agent weredissolved into 100 mL of methyl isobutyl ketone as a solvent (C2), andthe resulting was stirred to obtain a reaction solution. Then, thereaction solution was dropped into 100 mL of isopropyl alcohol as asolvent (C3), which had been heated to 80° C. beforehand, at a droppingrate of 1 mL/min to carry out drop polymerization. The droppolymerization was carried out while keeping the temperature ofisopropyl alcohol at 80° C. After the dropping was completed, theresulting was matured at 80° C. for another 2 hours and then allowed tocool. The resulting was concentrated under reduced pressure anddissolved in 30 mL of acetone to obtain a water-soluble polymersolution. The obtained water-soluble polymer solution was added to 1000mL of n-hexane to form white precipitates, which were then separated asa residue by filtration. The obtained water-soluble polymer was washedwith n-hexane and then dried to obtain 48 g of a powder of thewater-soluble polymer (b-1).

Note that the chain transfer constant of methyl acrylate to methylisobutyl ketone at 50° C. is 0.001 or less.

Further, the water/octanol partition coefficient of dilauroyl peroxideis 10.1.

The obtained water-soluble polymer (b-1) was analyzed, and the resultsshowed that the obtained water-soluble polymer (b-1) was a mixture of awater-soluble polymer (B1), which is a compound represented by formula(11-1) below, and a water-soluble polymer (B2), which is a compoundrepresented by formula (2-1) below. The mass ratio, water-solublepolymer (B1):water-soluble polymer (B2), was 40:60. The compoundrepresented by the formula (11-1) also falls under the water-solublepolymer (B11).

The weight average molecular weight of the water-soluble polymer (b-1)was 2200.

0.1 part by mass of the water-soluble polymer (b-1) was dissolved in 100parts by mass of water, and the surface tension of the resulting wasmeasured and found to be 35 mN/m.

Production Example 3: Production of Water-Soluble Polymer (b-2)

46 g of a powder of water-soluble polymer (b-2) was obtained in the samemanner as in Production Example 2, except that 6 g of dilauroyl peroxidewas used as the polymerization initiator, 100 mL of ethyl acetate wasused as the solvent (C2), and 100 mL of ethyl acetate was used insteadof the solvent (C3).

Note that the chain transfer constant of methyl acrylate to ethylacetate at 50° C. is 0.001 or less.

The obtained water-soluble polymer (b-2) was analyzed, and the resultsshowed that the obtained water-soluble polymer (b-2) was a water-solublepolymer (B1), which is a compound represented by the above formula(11-1), and included no water-soluble polymer (B2).

The weight average molecular weight of the water-soluble polymer (b-2)was 5300.

0.1 part by mass of the water-soluble polymer (b-2) was dissolved in 100parts by mass of water, and the surface tension of the resulting wasmeasured and found to be 28 mN/m.

Production Example 4: Production of Water-Soluble Polymer (b-3)

45 g of a powder of water-soluble polymer (b-3) was obtain in the samemanner as in Production Example 2, except that 3 g ofazobis-methylbutyronitrile was used as the polymerization initiator and100 mL of isopropyl alcohol was used instead of the solvent (C2).

Note that the chain transfer constant of methyl acrylate to isopropylalcohol at 50° C. is 0.0013.

The obtained water-soluble polymer (b-3) was analyzed, and the resultsshowed that the obtained water-soluble polymer (b-3) was a mixture of awater-soluble polymer (B1), which is a compound represented by theformula (11-1), a water-soluble polymer (B2), which is a compoundrepresented by the formula (2-1), and a water-soluble polymer (B2),which is a compound represented by formula (2-2) shown below. The massratio, water-soluble polymer (B1): water-soluble polymer (B2), was10:90.

The weight average molecular weight of the water-soluble polymer (b-3)was 1100.

0.1 part by mass of the water-soluble polymer (b-3) was dissolved in 100parts by mass of water, and the surface tension of the resulting wasmeasured and found to be 56 mN/m.

Example 1

1.8 parts by mass of the conductive polymer (a-1), 0.2 parts by mass ofthe water-soluble polymer (b-1), 94 parts by mass of water, and 4 partsby mass of isopropyl alcohol (IPA) were mixed together to prepare aconductive composition with a solids concentration of 2% by mass.

With respect to the obtained conductive composition, the amount of theconductive polymer (a-1) was 1.8% by mass, the amount of thewater-soluble polymer (B1) was 0.08% by mass, the amount of thewater-soluble polymer (B2) was 0.12% by mass, and the sum of the amountsof water and isopropyl alcohol was 98% by mass, each based on the totalmass of the conductive composition.

Further, the amount of the conductive polymer (a-1) was 90% by mass, theamount of the water-soluble polymer (B1) was 4% by mass, and the amountof the water-soluble polymer (B2) was 6% by mass, each based on a totalmass of solid components of the conductive composition.

The obtained conductive composition was evaluated in terms ofcoatability and conductivity. The results are shown in Table 1.

Example 2

1.98 parts by mass of the conductive polymer (a-1), 0.02 parts by massof the water-soluble polymer (b-1), 94 parts by mass of water, and 4parts by mass of isopropyl alcohol were mixed together to prepare aconductive composition.

With respect to the obtained conductive composition, the amount of theconductive polymer (a-1) was 1.98% by mass, the amount of thewater-soluble polymer (B1) was 0.008% by mass, the amount of thewater-soluble polymer (B2) was 0.012% by mass, and the sum of theamounts of water and isopropyl alcohol was 98% by mass, each based onthe total mass of the conductive composition.

Further, the amount of the conductive polymer (a-1) was 99% by mass, theamount of the water-soluble polymer (B1) was 0.4% by mass, and theamount of the water-soluble polymer (B2) was 0.6% by mass, each based ona total mass of solid components of the conductive composition.

The obtained conductive composition was evaluated in terms ofcoatability and conductivity. The results are shown in Table 1.

Example 3

1.8 parts by mass of the conductive polymer (a-1), 0.2 parts by mass ofthe water-soluble polymer (b-2), 94 parts by mass of water, and 4 partsby mass of isopropyl alcohol were mixed together to prepare a conductivecomposition.

With respect to the obtained conductive composition, the amount of theconductive polymer (a-1) was 1.8% by mass, the amount of thewater-soluble polymer (B1) was 0.2% by mass, the amount of thewater-soluble polymer (B2) was 0% by mass, and the sum of the amounts ofwater and isopropyl alcohol was 98% by mass, each based on the totalmass of the conductive composition.

Further, the amount of the conductive polymer (a-1) was 90% by mass, theamount of the water-soluble polymer (B1) was 10% by mass, and the amountof the water-soluble polymer (B2) was 0% by mass, each based on a totalmass of solid components of the conductive composition.

The obtained conductive composition was evaluated in terms ofcoatability and conductivity. The results are shown in Table 1.

Example 4

1.98 parts by mass of the conductive polymer (a-1), 0.02 parts by massof the water-soluble polymer (b-1), 94 parts by mass of water, and 4parts by mass of isopropyl alcohol were mixed together to prepare aconductive composition.

With respect to the obtained conductive composition, the amount of theconductive polymer (a-1) was 1.98% by mass, the amount of thewater-soluble polymer (B1) was 0.02% by mass, the amount of thewater-soluble polymer (B2) was 0% by mass, and the sum of the amounts ofwater and isopropyl alcohol was 98% by mass, each based on the totalmass of the conductive composition.

Further, the amount of the conductive polymer (a-1) was 99% by mass, theamount of the water-soluble polymer (B1) was 1% by mass, and the amountof the water-soluble polymer (B2) was 0% by mass, each based on a totalmass of solid components of the conductive composition.

The obtained conductive composition was evaluated in terms ofcoatability and conductivity. The results are shown in Table 1.

Comparative Example 1

1.8 parts by mass of the conductive polymer (a-1), 0.2 parts by mass ofthe water-soluble polymer (b-3), 94 parts by mass of water, and 4 partsby mass of isopropyl alcohol were mixed together to prepare a conductivecomposition.

With respect to the obtained conductive composition, the amount of theconductive polymer (a-1) was 1.8% by mass, the amount of thewater-soluble polymer (B1) was 0.02% by mass, the amount of thewater-soluble polymer (B2) was 0.18% by mass, and the sum of the amountsof water and isopropyl alcohol was 98% by mass, each based on the totalmass of the conductive composition.

Further, the amount of the conductive polymer (a-1) was 90% by mass, theamount of the water-soluble polymer (B1) was 1% by mass, and the amountof the water-soluble polymer (B2) was 9% by mass, each based on a totalmass of solid components of the conductive composition.

The obtained conductive composition was evaluated in terms ofcoatability and conductivity. The results are shown in Table 1.

TABLE 1 Comp. Ex. 1 Ex. 2 Ex. 3 Ex. 4 Ex. 1 Conductive Type a-1 a-1 a-1a-1 a-1 polymer (A) Amount [Part 1.8 1.98 1.8 1.98 1.8 by mass]Water-soluble Type b-1 b-1 b-2 b-2 b-3 polymer (B) Amount [Part 0.2 0.020.2 0.02 0.2 by mass] Polymerization LPO LPO LPO LPO AMBN initiatorChain transfer n-DM n-DM n-DM n-DM n-DM agent Polymerization MIBK, IPAMIBK, IPA Ethyl Ethyl IPA solvent acetate acetate Solvent (C1) Water[Part 94 94 94 94 94 by mass] IPA [Part by 4 4 4 4 4 mass] Amount inConductive 1.8 1.98 1.8 1.98 1.8 conductive polymer (A) compositionWater-soluble 0.08 0.008 0.2 0.02 0.02 [% by mass] polymer (B1)Water-soluble 0.12 0.012 0 0 0.18 polymer (B2) Solvent (C1) 98 98 98 9898 Amount in Conductive 90 99 90 99 90 solids [% polymer (A) by mass]Water-soluble 4 0.4 10 1 1 polymer (B1) Water-soluble 6 0.6 0 0 9polymer (B2) Evaluation of Surface tension 27.9 45.7 30.6 43 49.6coatability [mN/m] Evaluation of Surface resistivity 6.41 × 10⁶ 2.67 ×10⁶ 2.94 × 10⁶ 1.32 × 10⁶ 5.32 × 10⁶ conductivity [Ω/□]

Abbreviations and acronyms in Table 1 stand for the following compounds.

LPO: Dilauroyl peroxide

AMBN: Azo-bis-methylbutyronitrile

n-DM: n-dodecyl mercaptan

MIBK: Methyl isobutyl ketone

IPA: Isopropyl alcohol

As evident from Table 1, comparison between Example 1, Example 3 andComparative Example 1 shows that, though the amount of the water-solublepolymer (b-1) or the water-soluble polymer (b-2) and the amount of thewater-soluble polymer (b-3) were the same, the conductive compositionsobtained in Examples 1 and 3 had a lower surface tension and hence asuperior coatability as compared to the conductive composition obtainedin Comparative Example 1. In particular, the coating film formed fromthe conductive composition obtained in Example 3 had excellentconductivity.

Comparison between Example 2. Example 4 and Comparative Example 1 showsthat, though the amount of the water-soluble polymer (b-1) or thewater-soluble polymer (b-2) was smaller than the amount of thewater-soluble polymer (b-3), the conductive compositions obtained inExamples 2 and 4 had a lower surface tension and hence a superiorcoatability as compared to the conductive composition obtained inComparative Example 1. Further, though the solids concentrations of theconductive compositions obtained in Examples 2 and 4 and the solidsconcentration of the conductive composition obtained in ComparisonExample 1 were the same, the coating films formed from the conductivecompositions obtained in Examples 2 and 4 had a superior conductivity tothe coating film formed from the conductive composition obtained inComparative Example 1.

Example 5

1.4 parts by mass of the conductive polymer (a-1), 0.2 parts by mass ofthe water-soluble polymer (b-1), 94 parts by mass of water, 4 parts bymass of isopropyl alcohol (IPA), and 0.4 parts by mass of pyridine weremixed together to prepare a conductive composition with a solidsconcentration of 2% by mass.

With respect to the obtained conductive composition, the amount of theconductive polymer (a-1) was 1.4% by mass, the amount of thewater-soluble polymer (B1) was 0.08% by mass, the amount of thewater-soluble polymer (B2) was 0.12% by mass, the sum of the amounts ofwater and isopropyl alcohol was 98% by mass, and the amount of pyridinewas 0.4% by mass, each based on the total mass of the conductivecomposition.

Further, the amount of the conductive polymer (a-1) was 70% by mass, theamount of the water-soluble polymer (B1) was 4% by mass, the amount ofthe water-soluble polymer (B2) was 6% by mass, and the amount ofpyridine was 20% by mass, each based on a total mass of solid componentsof the conductive composition.

The obtained conductive composition was evaluated in terms ofcoatability, conductivity and influence on resist layer. The results areshown in Table 2.

Example 6

1.52 parts by mass of the conductive polymer (a-1), 0.02 parts by massof the water-soluble polymer (b-1), 94 parts by mass of water, 4 partsby mass of isopropyl alcohol (IPA), and 0.46 parts by mass of pyridinewere mixed together to prepare a conductive composition with a solidsconcentration of 2% by mass.

With respect to the obtained conductive composition, the amount of theconductive polymer (a-1) was 1.52% by mass, the amount of thewater-soluble polymer (BI) was 0.008% by mass, the amount of thewater-soluble polymer (B2) was 0.012% by mass, the sum of the amounts ofwater and isopropyl alcohol was 98% by mass, and the amount of pyridinewas 0.46% by mass, each based on the total mass of the conductivecomposition.

Further, the amount of the conductive polymer (a-1) was 76% by mass, theamount of the water-soluble polymer (B1) was 0.4% by mass, the amount ofthe water-soluble polymer (B2) was 0.6% by mass, and the amount ofpyridine was 23% by mass, each based on a total mass of solid componentsof the conductive composition.

The obtained conductive composition was evaluated in terms ofcoatability, conductivity and influence on resist layer. The results areshown in Table 2.

Comparative Example 2

A conductive composition with a solids concentration of 2% by mass wasprepared in the same manner as in Comparative Example 1.

With respect to the obtained conductive composition, the amount of theconductive polymer (a-1) was 1.8% by mass, the amount of thewater-soluble polymer (B1) was 0.02% by mass, the amount of thewater-soluble polymer (B2) was 0.18% by mass, and the sum of the amountsof water and isopropyl alcohol was 98% by mass, each based on the totalmass of the conductive composition.

Further, the amount of the conductive polymer (a-1) was 90% by mass, theamount of the water-soluble polymer (B1) was 1% by mass, and the amountof the water-soluble polymer (B2) was 9% by mass, each based on a totalmass of solid components of the conductive composition.

The obtained conductive composition was evaluated in terms ofcoatability, conductivity and influence on resist layer. The results areshown in Table 2.

TABLE 2 Ex. 5 Ex. 6 Comp. Ex. 2 Conductive Type a-1 a-1 a-1 polymer (A)Amount [Part 1.4 1.52 1.8 by mass] Water-soluble Type b-1 b-1 b-3polymer (B) Amount [Part 0.2 0.02 0.2 by mass] Polymerization LPO LPOAMBN initiator Chain transfer n-DM n-DM n-DM agent Polymerization MIBK,IPA MIBK, IPA IPA solvent Solvent (C1) Water [Part 94 94 94 by mass] IPA[Part by 4 4 4 mass] Basic Type Py Py — compound (D) Amount [Part 0.40.46 0 by mass] Amount in Conductive 1.4 1.52 1.8 conductive polymer (A)composition Water-soluble 0.08 0.008 0.02 [% by mass] polymer (B1)Water-soluble 0.12 0.012 0.18 polymer (B2) Solvent (C1) 98 98 98 Basiccompound 0.4 0.46 0 (D) Amount in Conductive 70 76 90 solids [% polymer(A) by mass] Water-soluble 4 0.4 1 polymer (B1) Water-soluble 6 0.6 9polymer (B2) Basic compound 20 23 0 (D) Evaluation of Surface tension27.9 45.7 49.6 coatability [mN/m] Evaluation of Surface resistivity 6.41× 10⁶ 2.67 × 10⁶ 5.32 × 10⁶ conductivity [Ω/□] Evaluation of A A Binfluence on resist

Abbreviations and acronyms in Table 2 stand for the following compounds.

LPO: Dilauroyl peroxide

AMBN: Azo-bis-methylbutyronitrile

n-DM: n-dodecyl mercaptan

MIBK: Methyl isobutyl ketone

IPA: Isopropyl alcohol

Py: Pyridine

As evident from Table 2, comparison between Example 5 and ComparativeExample 2 shows that, though the amount of the water-soluble polymer(b-1) and the amount of the water-soluble polymer (b-3) were the same,the conductive composition obtained in Example 5 had a lower surfacetension and hence a superior coatability as compared to the conductivecomposition obtained in Comparative Example 2. From the conductivecomposition obtained in Example 5, a conductive film with less filmreduction of the resist layer, i.e., with less influence on the resistlayer, could be formed.

Comparison between Example 6 and Comparative Example 2 shows that,though the amount of the water-soluble polymer (b-1) was smaller thanthe amount of the water-soluble polymer (b-3), the conductivecomposition obtained in Example 6 had a lower surface tension and hencea superior coatability as compared to the conductive compositionobtained in Comparative Example 2. Further, though the solidsconcentration of the conductive composition obtained in Example 6 andthe solids concentration of the conductive composition obtained inComparison Example 2 were the same, the coating film formed from theconductive composition obtained in Example 6 had a superior conductivityto the coating film formed from the conductive composition obtained inComparative Example 2. From the conductive composition obtained inExample 6, a conductive film with less film reduction of the resistlayer, i.e., with less influence on the resist layer, could be formed.

INDUSTRIAL APPLICABILITY

The conductive composition of the present invention can form a coatingfilm with excellent coatability and conductivity and hence can be usedas an antistatic agent applicable even to the semiconductor devices ofthe next-generation process.

1. A conductive composition comprising a conductive polymer (A), awater-soluble polymer (B), and a solvent (C1), wherein: thewater-soluble polymer (B) comprises a water-soluble polymer (B11)represented by formula (11), and an amount of a water-soluble polymer(B2) represented by formula (2) as the water-soluble polymer (B) is0.15% by mass or less, based on a total mass of the conductivecomposition:

wherein R¹ denotes a linear or branched alkyl group with 6 to 20 carbonatoms, Y¹ denotes a single bond, —S—, —S(═O)—, —C(═O)—O— or —O—, p1denotes an average number of repetitions and is a number of from 1 to50, and m denotes a number of from 1 to 5; and

wherein each of R⁴ and R⁵ independently denotes a methyl or ethyl group,R⁶ denotes a hydrophilic group, R⁷ denotes a hydrogen atom or a methylgroup, Z denotes a cyano group or a hydroxy group, and q denotes anaverage number of repetitions, and is a number of from 1 to
 50. 2. Theconductive composition according to claim 1, wherein a water/octanolpartition coefficient (Log P) for polymerization initiator-derivedcomponents in the water-soluble polymer (B) is 8.50 or more.
 3. Theconductive composition according to claim 1, wherein the conductivepolymer (A) is polyaniline sulfonic acid.
 4. The conductive compositionaccording to claim 2, wherein the conductive polymer (A) is polyanilinesulfonic acid.
 5. A conductive composition comprising a conductivepolymer (A), a water-soluble polymer (B), a solvent (C1), and a basiccompound (D), wherein: the water-soluble polymer (B) comprises awater-soluble polymer (B1) represented by formula (1), and an amount ofa water-soluble polymer (B2) represented by formula (2) as thewater-soluble polymer (B) is 0.15% by mass or less, based on a totalmass of the conductive composition:

wherein R¹ denotes a linear or branched alkyl group with 6 to 20 carbonatoms, R² denotes a hydrophilic group, R³ denotes a hydrogen atom or amethyl group, Y¹ denotes a single bond, —S—, —S(═O)—, —C(═O)—O— or —O—,and p1 denotes an average number of repetitions and is a number of from1 to 50; and

wherein each of R⁴ and R⁵ independently denotes a methyl or ethyl group,R⁶ denotes a hydrophilic group, R⁷ denotes a hydrogen atom or a methylgroup, Z denotes a cyano group or a hydroxy group, and q denotes anaverage number of repetitions, and is a number of from 1 to
 50. 6. Theconductive composition according to claim 5, wherein a water/octanolpartition coefficient (Log P) for polymerization initiator-derivedcomponents in the water-soluble polymer (B) is 8.50 or more.
 7. Theconductive composition according to claim 5, wherein the conductivepolymer (A) is polyaniline sulfonic acid.
 8. The conductive compositionaccording to claim 6, wherein the conductive polymer (A) is polyanilinesulfonic acid.
 9. A water-soluble polymer represented by formula (3):

wherein R⁸ denotes a linear or branched alkyl group with 6 to 20 carbonatoms, R⁹ denotes a hydrophilic group, R¹⁰ denotes a hydrogen atom or amethyl group, Y² denotes a single bond, —C(═O)—O— or —O—, and p2 denotesan average number of repetitions and is a number of more than 1 and notmore than
 50. 10. A method for producing a water-soluble polymer (B)comprising a water-soluble polymer (B1) represented by formula (1), themethod comprising a polymerization step of polymerizing a water-solublevinyl monomer in a solvent (C2) satisfying condition 1 in the presenceof a polymerization initiator having a terminal hydrophobic group:Condition 1: a chain transfer constant of methyl acrylate to the solvent(C2) at 50° C. is 0.001 or less.

wherein R¹ denotes a linear or branched alkyl group with 6 to 20 carbonatoms, R² denotes a hydrophilic group, R³ denotes a hydrogen atom or amethyl group, Y¹ denotes a single bond, —S—, —S(═O)—, —C(═O)—O— or —O—,and p1 denotes an average number of repetitions and is a number of from1 to
 50. 11. The method according to claim 10, wherein thepolymerization step is performed in the presence of a chain transferagent having a terminal hydrophobic group.
 12. A method for producing aconductive composition, comprising a step of producing the water-solublepolymer (B) by the method of claim 10, and a step of mixing the obtainedwater-soluble polymer (B) with a conductive polymer (A) and a solvent(C1).
 13. The method according to claim 12, wherein the polymerizationstep is performed in the presence of a chain transfer agent having aterminal hydrophobic group.
 14. The method according to claim 12,wherein the water-soluble polymer (B) is mixed with a basic compound (D)in addition to the conductive polymer (A), and the solvent (C1).
 15. Themethod according to claim 13, wherein the water-soluble polymer (B) ismixed with a basic compound (D) in addition to the conductive polymer(A), and the solvent (C1).